Izumi Nakai | Tokyo University of Science (original) (raw)

Papers by Izumi Nakai

Open Journal of Archaeometry, 2013

In this article we report a comparative study on excavated objects and artifact from museums to r... more In this article we report a comparative study on excavated objects and artifact from museums to reveal an aspect of ancient trade. The target artifact is Western Asiatic cast ribbed rectangular beads excavated from an architectural remain at Kaman-Kalehöyük, Turkey. Blue glass beads of this type have been excavated in Western Asia from north Iran and Iraq to the Syro-Palestinian coast from second half of 16th to 14th century BC. The analysis of the samples was carried out by using a portable Xray fluorescence (XRF) spectrometer developed by us. The instrument was brought to the excavation site in Turkey as well as to the museums to analyse typologically similar glass beads from the collection of Okayama Orient Museum and MIHO MUSEUM in Japan, for comparison. Our XRF analyses suggested that all analysed glass artifacts are plant ash sodalime silica glass with 2-4 wt% magnesium and potassium. The three glass beads exhibited similar compositional characteristic, i.e. they contain Sb, P...

Journal of Synchrotron Radiation, 2001

A new laboratory spectrometer for X-ray Induced Electron Emission Spectroscopy (XIEES) has been d... more A new laboratory spectrometer for X-ray Induced Electron Emission Spectroscopy (XIEES) has been developed. This spectrometer is suitable for measurements of X-ray Absorption Fine Structure (XAFS) spectrum in surface sensitive fluorescence and electron emission detection modes as well as in standard transmission mode. It is the advantage of this spectrometer that a wide range of X-ray energy scanning between 0.48 and 41 keV is available. At the Cu K-edge, an energy resolution of about 2 eV has been achieved. The spectrometer has been used to analyze the Al2O3 (40 Å and 500 Å)/Si(100) with total electron yield measurement.

Journal of Solid State Chemistry, 2001

Chemical states and structural changes accompanying the electrochemical Li deintercalation of Li ... more Chemical states and structural changes accompanying the electrochemical Li deintercalation of Li 1؊x (Mn, M) 2 O 4 (M ‫؍‬ Cr, Co, Ni) were studied by the in situ X-ray absorption 5ne structure (XAFS) technique. The X-ray absorption near-edge structures (XANES) of Mn and M as a function of x showed that the high voltage (&5 V) in the cathode materials of an Li secondary battery is due to the oxidation of M 3؉ to M 4؉ (M ‫؍‬ Cr, Co) and M 2؉ to M 4؉ (in the case of M ‫؍‬ Ni), while the origin of the low voltage (3.9+4.3 V) can be ascribed to the oxidation of Mn 3؉ to Mn 4؉. The extended X-ray absorption 5ne structure (EXAFS) analysis of Li 1؊x (Mn, Ni) 2 O 4 revealed that Ni 2؉ is oxidized to Ni 4؉ via the Ni 3؉ state with a Jahn+Teller distorted Ni 3؉ +O octahedron.

Journal of Mineralogical and Petrological Sciences, 2008

Znbearing beaverite occurs as a secondary mineral in an oxidized zone of a quartz vein in the hyd... more Znbearing beaverite occurs as a secondary mineral in an oxidized zone of a quartz vein in the hydrothermal Cu-Zn-Pb ore deposit of the Mikawa mine, Niigata Prefecture, Japan. The Znbearing beaverite is dark brown in color with streaks and the associated minerals are quartz, galena, sphalerite, pyrite, anglesite, beaverite, orthoclase, and osarizawaite. The empirical formula of the mineral based on EPMA is Pb 0.95 (Fe 1.88 Al 0.10) Σ1.98 (Zn 0.83 Cu 0.30) Σ1.13 (SO 4) 2 [O 0.38 (OH) 5.36 ] Σ5.74 for S = 2, which leads to the ideal formula Pb(Fe 2 Zn)(SO 4) 2 (OH) 6. The crystal structure is refined by Rietveld analysis in the space group R3 ￣ m. Using powder XRD data obtained by the combined use of a Gandolfi camera and monochromatic synchrotron radiation, the following values are obtained: a = 7.3028(2), c = 17.0517 (4) Å, V = 787.56(4) Å 3 , and D calc = 4.25 g/cm 3 .

Journal of Forensic Sciences, 2009

High-energy synchrotron radiation x-ray fluorescence spectrometry (SR-XRF) utilizing 116 keV x-ra... more High-energy synchrotron radiation x-ray fluorescence spectrometry (SR-XRF) utilizing 116 keV x-rays was used to characterize titanium dioxide pigments (rutile) and automotive white paint fragments for forensic examination. The technique allowed analysis of K lines of 9 trace elements in 18 titanium dioxide pigments (rutile), and 10 trace elements in finish coat layers of seven automotive white paint fragments. Highfield strength elements (HFSE) were found to strongly reflect the origin of the titanium dioxide (TiO 2) pigments, and could be used as effective parameters for discrimination and classification of the pigments and paint fragments. A pairwise comparison of the finish coat layers of seven automotive white paint fragments was performed. The trace elements in the finish coat layers detected by the high-energy SR-XRF were especially effective for identification. By introducing the trace element information of primer and electrocoat layers, all the automotive white paint fragments could be discriminated by this technique.

Japanese Magazine of Mineralogical and Petrological Sciences, 2001

Chemistry Letters, 2011

ABSTRACT High-energy (116 keV) synchrotron radiation X-ray fluorescence analysis has for the firs... more ABSTRACT High-energy (116 keV) synchrotron radiation X-ray fluorescence analysis has for the first time been applied to the quantitative analysis of trace heavy elements of geological samples. Calibration curves for the determination of trace heavy elements were obtained by measuring 7 reference rock samples and showed good linearity because of the high penetrating power of the high-energy X-rays. It is found that this method is suitable for rapid and nondestructive quantitative characterization of trace heavy elements in trace amount of soil samples for forensic investigation.

Antarctic Meteorite …, 2000

Deposits in the water tank at the Dome Fuji Station were collected by the 37th Japanese Antarctic... more Deposits in the water tank at the Dome Fuji Station were collected by the 37th Japanese Antarctic Research Expedition team in 1996. We recovered 233 micrometeorites from the deposits. A consortium study was started in late 1998 to investigate mineralogy, petrology, bulk chemistry, and isotopic composi tions of the micrometeorites. This is the first case of an organized study of micrometeorites in Japan, in order to establish the methods to investigate micrometeorites routinely. Consortium results on mineralogy, petrology, minor and trace element compositions, isotopic compositions of noble gases of the micrometeorites are reported in this volume. We also found a sequence of mineralogical and compositional changes of micrometeorites experienced from frictional heating during atmospheric entry. INAA and ion probe studies are now in progress.

Antarctic Meteorite …, 1999

Antarctic micrometeorites (AMMs) were found among the precipitated fi ne particles recovered from... more Antarctic micrometeorites (AMMs) were found among the precipitated fi ne particles recovered from a water tank in the Dome Fuji Station. These AMMs had been contained in the recent fallen snow around the station. Initial processing of the precipitated particles revealed that they were dominated by natural and artifi cial terrestrial materials, thus a series of processes were developed to separate AMMs from terrestrial particles. The recovery rate of AMMs by the processes was approximately 45% in weight, which was determined from a weight ratio of recovered/accreted AMMs. The micro-morphology and major-element concentration of the recovered AMMs were characterized. They appear to have been heated upon atmospheric entry to varying temperatures and can be classifi ed into two major types based on the degree of heating: (1) fi ne-grained, irregular-shaped, partial-melted micrometeorites with chondritic composition, and (2) total-melted spherical micrometeorites with chondritic composition except for volatile elements. A digital catalog for the AMMs identified in this study was established on the web site [URL: http://dust.cc.gakushuin.ac.jp/], in which optical characteristics, high-resolution images, and chemical compositions of individual AMMs are presented. The AMMs listed in the catalog are the first Japanese collection of extraterrestrial dust. The criterion and techniques developed for the selection and initial analysis of AMMs are applicable for the dust samples that are being collected by the 39th Japanese Antarctic Research Expedition team.

Physica B: Condensed Matter, 1995

XANES spectra of chemical species in high temperature flame were measured for the first time util... more XANES spectra of chemical species in high temperature flame were measured for the first time utilizing apparatus of atomic absorption spectroscopy and synchrotron radiation. Metal nitrate solution [1 M] was introduced into an air-acetylene flame (ca. 2000°C) through nebulizer. Small monochromated X-ray beam was passed through the flame so that its XANES spectra were successfully measured in fluorescence mode. XANES spectra of free atoms were detected for the nitrate solutions of Cu and Ni, but not for those of Sr and Rb, which have low ionization potentials and low atomization efficiency and may exist as ionized species such as free ions, oxides, etc. in the flame.

Denki Kagaku oyobi Kogyo Butsuri Kagaku, 1998

NIPPON KAGAKU KAISHI, 1984

X-Ray Spectrometry, 2006

... Yoshinori Nishiwaki,1∗ Toshio Nakanishi,1 Yasuko Terada,2 Toshio Ninomiya2 and Izumi Nakai3 .... more ... Yoshinori Nishiwaki,1∗ Toshio Nakanishi,1 Yasuko Terada,2 Toshio Ninomiya2 and Izumi Nakai3 ... ŁCorrespondence to: Yoshinori Nishiwaki, Forensic Science Laboratory, Hyogo Prefectural Police Headquarters, Shimoyamate-dori, Chuo-ku, Kobe, Hyogo 650-8510, Japan. ... Te ...

The Journal of Physical Chemistry B, 2006

Structure analysis of unilamellar manganese oxide nanosheets obtained via exfoliation of layered ... more Structure analysis of unilamellar manganese oxide nanosheets obtained via exfoliation of layered manganese oxides was carried out utilizing synchrotron radiation (SR) X-ray in-plane diffraction and polarization-dependent total reflection fluorescence X-ray absorption fine structure (PTRF-XAFS) analyses. A combination of SR excitation and the total reflection of incoming X-rays provides signals strong enough for both analyses even from a monolayer of the MnO 2 nanosheets having a concentration of 0.7 µg cm-2. In addition, the mean oxidation state of constituent manganese ions in the MnO 2 sheets was estimated on the basis of XANES spectra, and bond valence sum calculations with the bond length obtained from the present EXAFS analyses. The obtained structural data revealed that the two-dimensional lattice of the MnO 2 sheets underwent a slight elongation upon delamination. These changes correspond to approximately 1% expansion of sheet area and 1-2% expansion of thickness, which can be understood by reduction of the mean oxidation number of manganese ions in the sheet through the exfoliation process.