Vol. 51 No. 8
August, 2002
Hirofumi Kondo**
**Sony Corporation, Sendai Technology Center, 3-4-1, Sakuragi, Tagajo-shi, Miyagi 985-0842
(Received 2 May 2002)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.
Keywords : magnetic media; surface analysis; tribology; carbon protective layer; lubricant.
Hitoshi Hoshino**
**Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai 980-8579
(Received 16 May 2002, Accepted 5 June 2002)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.
Keywords : metal complex; HPLC; precolumn complexation; trace metal analysis.
Kouichi Tsuji**
**Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577
(Received 8 April 2002, Accepted 10 June 2002)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.
Keywords : grazing-exit; XRF; EPMA; PIXE; STM.
Yuetsu Danzaki**
**Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577
(Received 29 November 2001, Accepted 27 May 2002)Tin alloys have generally been dissolved in HNO3-HCl-tartaric acid and measured by inductively coupled plasma-optical emission spectrometry (ICP-OES). However, alloys containing Ag are precipitated as AgCl by dissolution with a mixed acid containing HCl. Therefore, as a method for not precipitating Ag and Sn it was performed by HNO3-HF dissolution. By using the dissolution method, Ag-In-Sn alloys could be measured by ICP-OES. Moreover, the dissolution method was applied to Cu-In-Sn alloys and Ag-In-Sb mixed samples. After measuring by ICP-OES, it was calculated by the sequential correction method, which involver correcting the fluctuations in the emission intensities, the impurities in standard reagents, any spectral interferences or non-spectral interferences, and the blank values.
Keywords : HNO3-HF dissolution; sequential correction method; Ag-In-Sn alloys; Cu-In-Sn alloys; Ag-In-Sb mixed samples; ICP-OES.
Yuetsu Danzaki**
**Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577
(Received 28 January 2002, Accepted 27 May 2002)For trace analysis in high-purity materials by inductively coupled plasma-optical emission spectrometry (ICP-OES), concentration separation is necessary. It was performed by coprecipitation separation with cupferron, and measured by ICP-OES to perform quantitative analysis of Ti, Zr, Hf, V, Nb, Ta, Mo and Ga as impurities in pure iron, iron alloys and iron oxide. The detection limits of the impurities were made smaller by correcting for fluctuation of the emission intensities in measurements and spectral interferences of Fe for the impurities.
Keywords : impurities; cupferron separation; pure iron; iron alloys; iron oxide; ICP-OES.
Tetsuo Hashimoto, Takahiro Nakagawa, Hayato Usuda and Takashi Yawata*
Faculty of Science, Niigata University, 8050, Ikarashi-ninocho, Niigata 950-2181
(Received 8 April 2002, Accepted 27 May 2002)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.
Keywords : radiation-induced luminescence; radiation dosimetry; thermoluminescence; optically stimulated luminescence; naturally accumulated dose; luminescence dating; luminescence measuring system; quartz and feldspar.
Yorie Kaneko, Masaki Ohata, Naoki Furuta*, Yuya Kubo and Tsugunori Inaba**
*Faculty of Science and Engineering, Department of Applied Chemistry, Chuo University, 1-13-27, Kasuga, Bunkyo-ku, Tokyo 112-8551
**Faculty of Science and Engineering, Department of Electrical, Electronic, and Communication Engineering, Chuo University, 1-13-27, Kasuga, Bunkyo-ku, Tokyo 112-8551
(Received 11 March 2002, Accepted 9 June 2002)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.
Keywords : arc plasma treatment; fly ash; slag; chalcophile elements; ICP-AES/MS.
Yuji Suzuki*
*Saitama Prefectural University Junior College, 820, Sannomiya, Koshigaya-shi, Saitama 343-8540
(Received 25 December 2001, Accepted 3 June 2002)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.
Keywords : serum albumin/globulin ratio; spectrophotometry; p-nitrobenzaldehyde; Bromocresol Green.
Kenji Kurihara, Fumiyo Tsuchiya and Tadao Shoji*
*Analysis Center, Dainippon Ink & Chemicals, Inc., 631, Sakado, Sakura-shi, Chiba 285-8668
(Received 10 April 2002, Accepted 27 May 2002)Keywords : GC/MS; high-frequency; hindered amine light stabilizer.
Hitoshi Yamaguchi, Shinji Itoh*, Shukuro Igarashi** and Takeshi Kobayashi*
*National Institute for Materials Science, 1-2-1, Sengen, Tsukuba-shi, Ibaraki 305-0047
**Department of Materials Science, Faculty of Engineering, Ibaraki University, 4-12-1, Nakanarusawa, Hitachi-shi, Ibaraki 316-8511
(Received 17 April 2002, Accepted 5 July 2002)Keywords : determination of trace of total silicon; high-purity copper; molybdosilicic acid blue spectrophotometry; silicon fluoride separation.
Junichi Isoe*, Emiko Kaneko**, Suwaru Hoshi and Kunihiko Akatsuka*
*Department of Applied and Environmental Chemistry, Graduate School of Engineering, Kitami Institute of Technology, 165, Koen-cho, Kitami-shi, Hokkaido 090-8507
**Department of Applied and Environmental Chemistry, Kitami Institute of Technology, 165, Koen-cho, Kitami-shi, Hokkaido, 090-8507
(Received 10 June 2002, Accepted 3 July 2002)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.
Keywords : silicate; arsenic; quenching time profile; heteropolymolybdate ion; Rhodamine B.
Ryo Kato
Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578
(Awarded by Tohoku University dated March 25, 2002)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.
Keywords : anion recognition; hydrogen bonding; chromogenic sensing; thiourea; interface; dynamic interfacial tension; isothiourea.
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