BUNSEKI KAGAKU
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Volume 51, Issue 8
Displaying 1-12 of 12 articles from this issue
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Reviews
  • Surface analysis of magnetic thin film media
    Hirofumi KONDO
    2002 Volume 51 Issue 8 Pages 569-596
    Published: August 05, 2002
    Released on J-STAGE: March 13, 2009
    DOIhttps://doi.org/10.2116/bunsekikagaku.51.569
    JOURNAL FREE ACCESS
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    Magnetic recording technology is the most economic form of storage for many applications. The advantage of magnetic storage is that the storage density is increasing at a very rapid rate. Recently, with the introduction of thin film media and a magneto-resistive head, the storage densities are increasing at a rate of 100% per year, the storage density in hard disks reached 50 M bit/mm2 for production and 300 M bit/mm2 for demonstration. Diamond-like carbon (DLC) is applied over a Co-based magnetic layer as a smooth protective layer, and one to two monolayers of perfluoropolyether are used as a lubricant. The tribological properties of ultra-thin films have attracted considerable attention, because they can dramatically influence the tribological properties of recording media, which limits the storage density before we achieve the magnetic limit. The rapidly increasing storage density will soon require carbon overcoats of only 2 nm and a lubricant of less than 1 nm to achieve the above-mentioned recording density. Not only the film properties, but also the surface interaction have become a matter of importance in this region. In order to ensure the tribological properties and lifetime of the magnetic recording system, the lubricant molecule must be strongly attached to the carbon surface so that they can avoid spin-off from the rapidly rotating disks, depletion caused by head-media interactions, or simple displacement by adsorbed water or airborne organic compounds. Also, a strongly adsorbed lubricant leads to low friction and improve durability. This paper reviews conventional methods used to characterize these films and the interaction between carbon and the lubricant molecules. The prospect for the analysis of ultra-thin film from the standpoints of XPS, FTIR, Raman, EELS, Auger is also given.
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Accounts
  • Development of precolumn complexation-reversed-phase partition liquid chromatography for the ultratrace detection of metal ions
    Hitoshi HOSHINO
    2002 Volume 51 Issue 8 Pages 597-604
    Published: August 05, 2002
    Released on J-STAGE: March 13, 2009
    DOIhttps://doi.org/10.2116/bunsekikagaku.51.597
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    The analytical practicability of precolumn complexation-reversed-phase partition liquid chromatography in ultratrace metal detection has been exemplified by successful applications to aluminium determination in high-purity alkali hydroxide pellets and ground water samples. High sensitivity with extraordinary matrix toughness of the HPLC methods has been also emphasized with air-borne particulate analyses for beryllium, vanadium and nickel. The complexation reagents employed were tridentate ligands with N, O donor functions, such as 2,2'-dihydroxyazobenzene, H-resorcinol and some hydrazones. Additionally, an on-line preconcentration system connected to the HPLC has been shown for the detection of cobalt in the ppt range as the 4-(2-pyridylazo)resorcinolato complex. The underlying chemistry at work in the precolumn complexation-HPLC processes has been described in terms of the ultrahigh sensitivity and the specificity to certain metal ions. The kinetic aspect of the complex dissociation reactions potentially taking place during elution is crucial for designing the precolumn complexation HPLC to give unique kinetically-controlled selectivity to metal complexes.
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  • Localized surface analysis by grazing-exit X-ray spectrometry and a scanning tunneling microscope
    Kouichi TSUJI
    2002 Volume 51 Issue 8 Pages 605-612
    Published: August 05, 2002
    Released on J-STAGE: March 13, 2009
    DOIhttps://doi.org/10.2116/bunsekikagaku.51.605
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    Grazing-exit X-ray spectrometry, in which characteristic X-rays are measured at small takeoff angles, has been applied to several analytical methods: X-ray fluorescence (XRF), electron probe microanalysis (EPMA) and particle-induced X-ray emission (PIXE). It was found that the X-ray background intensity is reduced under grazing-exit conditions; as a result, the surface sensitivity is improved. Grazing-exit X-ray spectrometry is useful for surface, thin-film and particle analyses. It is possible to evaluate the density and thickness of thin films. Since the exciting probe can irradiate a sample surface at 90 degrees, localized surface and thin film analyses are possible. In addition, an experiment combining a scanning tunneling microscope (STM) and the X-ray analytical technique has been studied as a new type of micro-analytical method.
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Technical Papers
Research Papers
  • Development of an automated system equipped with a small X-ray irradiator for red/blue thermoluminescence and optically stimulated luminescence measurement from natural minerals
    Tetsuo HASHIMOTO, Takahiro NAKAGAWA, Hayato USUDA, Takashi YAWATA
    2002 Volume 51 Issue 8 Pages 625-632
    Published: August 05, 2002
    Released on J-STAGE: March 13, 2009
    DOIhttps://doi.org/10.2116/bunsekikagaku.51.625
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    Some white minerals, such as quartz and feldspars, are available for the accumulated radiation-dose evaluation or archaeological dating using luminescence measurements derived from interaction with radiation exposure. For the reliable dose-evaluation using a single aliquot regenerative-dose method (SAR), an automated system of luminescence measurement has been developed by incorporation with a small X-ray irradiator in addition to the elimination of black-body radiation as low as possible. The use of light guided pipe of glass core-rod type served to introduce effectively the luminescence to the sensitive area of photo-multiplier tube (PMT), which was cooled at -20°C. In the present system, two kinds of thermoluminescence (TL), such as blue TL (BTL) and red TL (RTL) from quartz grains, and two optically stimulated luminescence (OSL), including B-OSL from quartz grains exposed with blue light and IRSL with infrared light, could be measured with high detection efficiency.
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  • Analysis and leaching experiment of slag produced by an arc plasma treatment of fly ash
    Yorie KANEKO, Masaki OHATA, Naoki FURUTA, Yuya KUBO, Tsugunori INABA
    2002 Volume 51 Issue 8 Pages 633-640
    Published: August 05, 2002
    Released on J-STAGE: March 13, 2009
    DOIhttps://doi.org/10.2116/bunsekikagaku.51.633
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    A fly ash treatment is accompanied by the emission of hazardous elements. For mitigating the emission and reducing the volume of fly ash, we have conducted an arc plasma treatment. The elements in both fly ash and slag prepared by an arc plasma treatment were determined by inductively coupled plasma atomic emission spectrometry and mass spectrometry (ICP-AES/MS), and compared to each other. It was found that hazardous elements, such as Sb, As, Cd, Pb and Se, were concentrated in fly ash. Because these elements are volatile (chalcophile and siderophile elements), it is considered that they are vaporized during the arc plasma treatment. Leaching experiments were carried out to evaluate the advantages of the arc plasma treatment. It was evaluated that the proportion of leached elements from slag decreased with the arc plasma treatment compared to those without this treatment. Slag crucked into three different sizes was prepared, and a leaching experiment was conducted. The leached concentration of chalcophile elements did not change for slag cracked into three different sizes.
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Notes
  • Studies on the measurement method of the serum albumin/globulin ratio by combining the p-nitrobenzaldehyde method and the Bromocresol Green method
    Yuji SUZUKI
    2002 Volume 51 Issue 8 Pages 641-645
    Published: August 05, 2002
    Released on J-STAGE: March 13, 2009
    DOIhttps://doi.org/10.2116/bunsekikagaku.51.641
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    The determination method (NB method) for the serum albumin/globulin ratio by combining the Bromocresol Green (BCG) method for the serum albumin and the p-nitrobenzaldehyde (p-NITBA) method for the serum total globulin was compared with the conventional methods. The measurement values by the NB method correlated well with those by the BB method by combining the biuret method for the serum total protein and the BCG method (r=0.969, y=0.977x-0.151, Syx=0.095, n=100) and with those by the GB method combining the method of Goldenberg et al and the BCG method (r=0.984, y=0.898x-0.166, Syx=0.069, n=100). The mean value (1.31) of the NB method was lower than those of the BB method (1.49) and the GB method (1.64). The sum of the serum albumin and the serum total globulin obtained by the NB method correlated well with the serum total protein by the biuret method (r=0.970, y=1.036x+1.87, Syx=2.19g/l, n=100). From these results, it is thought that the NB method can be used to measure the serum albumin/globlin ratio.
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Technical Letters
Short Communication
  • Quenching time profile of Rhodamine B through ion association with heteropolymolybdate ion
    Junichi ISOE, Emiko KANEKO, Suwaru HOSHI, Kunihiko AKATSUKA
    2002 Volume 51 Issue 8 Pages 657-659
    Published: August 05, 2002
    Released on J-STAGE: March 13, 2009
    DOIhttps://doi.org/10.2116/bunsekikagaku.51.657
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    It has been found that the fluorescent intensity of Rhodamine B (Ex. 556 nm, Em. 570 nm) gradually decreases through ion association with the heteropolymolybdate ion. An investigation using molybdoarsenic acid demonstrates that quenching takes place over several minutes, depending on the arsenic concentration. Although the ion-association of the heteropolymolybdate ion has been the subject a number of investigations, there have as yet been no reports on the concentration dependence of the quenching time. Similar phenomena were observed for silicate and phosphate. The phenomena reported here will be a great aid in developing novel analytical methods for arsenic, phosphate and silicate, for which sensitive, yet simple, techniques are needed.
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Digest of Doctoral Dissertation
  • Synthesis of an anion-selective chromophore based on hydrogen bonding and its application to analytical chemistry
    Ryo KATO
    2002 Volume 51 Issue 8 Pages 661-662
    Published: August 05, 2002
    Released on J-STAGE: March 13, 2009
    DOIhttps://doi.org/10.2116/bunsekikagaku.51.661
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    The development of artificial receptors for anions is of current interest in host-guest chemistry. In a dissertation, chromogenic thiourea based receptors were designed, and their anion sensing functions were evaluated by 1H-NMR and UV-Vis spectroscopies. In acetonitrile-water, 1,3-di(4-nitrophenyl) thiourea exhibited an effective color change for acetate and aliphatic carboxylates, based on a strong hydrogen bond-mediated complexation of the receptor with these anions. Essentially no responses were observed for various inorganic anions, such as dihydrogenphosphate and halide anions. The application of the receptors to food analysis, was also examined; the receptors were found to be useful for the determination of acetate in vinegar. As charged receptors, isothiourea-based anion receptors were designed, and their anion recognition function at the 1,2-dichloroethane/water interface was examined by dynamic interfacial tensiometry. The complexation kinetics of a thiourea-induced isothiourea receptor with such anions as H2PO4- and Cl- was dependent on the receptor concentration. Both the saturated interfacial concentration and the adsorption constant of the thiourea-induced isothiourea receptor were found to be larger than those of a mono-substituted isothiourea receptor, exhibiting formation of an effective hydrogen bonding between isothiourea group and anion at the interface. Thus, the importance of the hydrogen bonding functions of the thiourea and isothiourea for anion recognition in the bulk solutions as well as at liquid/liquid interfaces was clarified in the present study.
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