All issues
Volume 55, Issue 6
Displaying 1-12 of 12 articles from this issue
- |<
- <
- 1
- >
- >|
Account
-
Kazuo YASUDA, Toshie YAGUCHI, Kuniyasu NAKAMURA, Yoshihiro HIRANO, Kic ...2006 Volume 55 Issue 6 Pages 357-367
Published: 2006
Released on J-STAGE: August 30, 2006
JOURNAL FREE ACCESSIt is said that a 0.1 portion of an atom or a 0.01 portion of a molecule can be detected with a newly developed method. However, the above values were employing a signal-to-noise ratio. We are measuring the numbers of shadows of objects, it is so-called signal, not the object, itself, at present. It is required to observe and measure the numbers of the object, itself, and discuss the signal-to-noise ratio in the observation. The concept of the present methodology is based on millions or billions of atoms, but observations or measurements at the atomic level are different using the above concept. The measurement of a group consisting of 100∼1000 atoms should be applied to another concept different from the existing one. The vaporization, reaction, phase transfer and observation of the detection limit in an alloy were studied by using a high-resolution electron microscope. It is thought that these three processes in the former are basically continuous phenomena, but it was found that they are intermittent phenomena. The key point in the above mentioned phenomena is the fact that it is related to the activity coefficient of the analyte atom in a binary alloy. Interactions between an analyte atom and co-existing or surrounding atoms occur as intermittent phenomena, like a geyser, so to say. This interaction is different from a conjugate bond between two kinds of atoms, and is recognized in the properties of an alloy. Upon observing to detection limit, a covering phenomenon over the analyte atom by sputtered surround atoms interferes with the radiation signal from the analyte. It can be said that the method of counting numbers of atoms is reliable compared with measuring the signal-to-noise ratio in this experiment.
View full abstractDownload PDF (1057K) -
Shinpei KADO, Keiichi KIMURA2006 Volume 55 Issue 6 Pages 369-380
Published: 2006
Released on J-STAGE: August 30, 2006
JOURNAL FREE ACCESSIt has been reported in the recent decade that molecular interactions in a variety of molecular pairs can be measured directly by using atomic force microscopy (AFM) as a highly sensitive and precise force sensor. The target molecules are immobilized covalently on AFM probe tips and substrates by utilizing self-assembled monolayers of thiol and organosilane derivatives. The AFM technique can be applied to novel analytical methods based on mechanochemical measurements of specific molecular interactions. In the present study, we directly measured the specific intermolecular forces for several functional molecules by AFM using the probe tip and substrate modified chemically with them. The target molecules used were crown ether and urea derivatives, which are host molecules possessing the abilities of cation-binding and hydrogen bonding, respectively, for analytical applications, and a photochromic spirobenzopyran derivative for a photochemical study. We demonstrated direct observations of the rupture forces of specific interactions based on their functionalities at a molecular level and an evaluation of the single forces. A promising application of the AFM methodology is also described, aiming at the development of an analytical method, such as a high-resolution chemical mapping based on direct AFM detection of a specific molecular interaction force.
View full abstractDownload PDF (675K) -
Masato OHNUMA, Jun-ichi SUZUKI2006 Volume 55 Issue 6 Pages 381-390
Published: 2006
Released on J-STAGE: August 30, 2006
JOURNAL FREE ACCESSThe microstructures of metal-nonmetal nano-granular soft magnetic films, precipitation hardened stainless steel and Al-Mg-Si alloys, have been studied by small-angle X-ray/neutron scattering (SAXS/SANS). Quantitative evaluation of average scale of their microstructures in nanometer scale has been accomplished by SAXS and SANS. Using this information, the contribution of the microstructures to the magnetic and mechanical properties are discussed in this paper.
View full abstractDownload PDF (862K)
Research Paper
-
Fujio IZUMI, Yukihiko KAWAMURA2006 Volume 55 Issue 6 Pages 391-395
Published: 2006
Released on J-STAGE: August 30, 2006
JOURNAL FREE ACCESSWe established a method for determining the three-dimensional distribution of nuclear densities from time-of-flight (TOF) neutron powder diffraction data measured with multiple detector banks. At first, the observed crystal-structure factors {Fo(h)} and standard deviations of |Fo(h)|'s estimated after Rietveld analysis using GSAS are output in text files, *.mem, with a file converter, Alchemy. After combining reflection data [hkl, Fo(h), σ{|Fo(hK)|}] in the *.mem files, so as to minimize the extinction effect in reflections with large interplanar spacings, they are analyzed by a maximum-entropy method program, PRIMA, to determine the nuclear densities in the unit cell. The resulting nuclear-density distribution is visualized in three dimensions with VEND. Such a procedure enabled us to visualize nuclear densities in Ni from TOF neutron powder diffraction data.
View full abstractDownload PDF (303K) -
Takayuki KONYA, Tetsuya OZAWA, Go FUJINAWA, Atsuko OONO, Toshihiro NAK ...2006 Volume 55 Issue 6 Pages 397-404
Published: 2006
Released on J-STAGE: August 30, 2006
JOURNAL FREE ACCESSThe crystal structure (Na96Al96Si96O384·183.7H2O) and the phase content of synthetic zeolite-A were determined by X-ray powder diffraction data using the Rietveld method. The result of a Rietveld refinement for a structure determination gave Rwp = 9.42% and S = 1.52. The electron density image, calculated with the maximum-entropy method, proved the reliablity of the refined crystal structure. The content of zeolite-A calculated by a scale factor obtained by the Rietveld refinement was 74.8 mass%, which was identical to the value of 74.3 mass% by Vonk's crystallinity analysis. The residue of zeolite-A might be an amorphous or amorphous-like phase. The number of bond water calculated by the Rietveld refinement was 184, the same as that of thermogravimetry.
View full abstractDownload PDF (3831K) -
Shigeki TAKAGO, Haruyuki YASUI, Kaoru AWAZU, Toshihiko SASAKI, Yukio H ...2006 Volume 55 Issue 6 Pages 405-410
Published: 2006
Released on J-STAGE: August 30, 2006
JOURNAL FREE ACCESSAn in-plane X-ray diffraction technique was used to measure the residual stress of a CVD (chemical vapor deposition) TiN -coated WC-Co alloy. We could obtain the diffraction pattern from a thin film layer, eliminating that of the substrate. In the case of a conventional X-ray diffractometer, the X-ray penetration depth is about few μm. However, for a grazing incidence beam it is only 0.2 μm. Depth profiles of residual stress in TiN film layer were evaluated by the present method and the conventional sin2Ψ technique. We concluded that the in-plane diffraction technique enables us to determine the residual stress in a CVD-TiN film having an oriented texture. It was found that the residual tensile stress generated a mismatch of the coefficient of thermal expansion between the film and the substrate.
View full abstractDownload PDF (511K) -
Masaharu KOIZUMI, Mitsuhiro HIRAI, Katsuaki INOUE2006 Volume 55 Issue 6 Pages 411-418
Published: 2006
Released on J-STAGE: August 30, 2006
JOURNAL FREE ACCESSAs is well known, α-lactalbumin (α-LA) and hen egg-white lysozyme (HEWL) are homologous with each other and closely similar in their ternary structures. On the other hand, their unfolding-folding processes were clarified to show different thermodynamic characteristics; however, the details of how such a difference relates to their structural transitions have not been clarified. In this report, based on an X-ray solution scattering method, we discuss the difference between the characteristics in the thermal structural transitions of α-LA and HEWL in solution at pH 7. A small-angle X-ray scattering (SAXS) method using a synchrotron radiation (SR) source was used for analyzing the protein structures in solutions, especially for studies of protein folding. For a long time the SR-SAXS method had provided us with low-resolution structural information, such as the radius of gyration obtained from SAXS data at a small-angle region. In the present study we observed the structural transitions of the above proteins in the wide-distance range from 2.5Å to 200Å, and analyzed the characteristics of the structural transition processes of the proteins, depending on all hierarchical structures (quaternary and ternary structures, domain structures and secondary structures). By using the method of SR-WAXS data analysis described in this report, we were able to analyze quantitatively and respectively the structural changes in a protein unfolding-refolding process, depending on different hierarchical structure levels and the structural transition cooperativeness between those structure levels, local structural changes, and so on. We show the recent development of an X-ray solution scattering method with significant improvements of the experimental resolutions in both time and space due to the use of third-generation SR sources, such as SPring-8 in Japan.
View full abstractDownload PDF (1631K) -
Takanori KIGUCHI, Naoki WAKIYA, Nobuyasu MIZUTANI, Kazuo SHINOZAKI2006 Volume 55 Issue 6 Pages 419-426
Published: 2006
Released on J-STAGE: August 30, 2006
JOURNAL FREE ACCESSThe interface structure and the chemical state on the orientation of a CeO2/YSZ (yttria stabilized zirconia)/Si and YSZ/CeO2/Si hetero structure have been considered using a high-resolution transmission electron microscope (HRETM) equipped with an analytical setup. Although both films showed a columnar structure, they had different orientations. In the YSZ/CeO2/Si hetero structure, the CeO2 layer has a (111) orientation without any in-plane orientation. TEM-EELS (electron energy loss spectroscopy) and TEM-EDS (energy dispersive X-ray spectroscopy) analyses showed that there were reacted interface layers due to a reduction of the CeO2 layer and the oxidation of the Si substrate. In the CeO2/YSZ/Si hetero structure, the CeO2 layer preferentially had a 001 orientation. The quality of the 001 orientation was increased on an ultra-thin YSZ layer. The interface of CeO2/YSZ (thick) has a semi-coherent interface with misfit dislocations. The interface of CeO2/YSZ (thin) has been ambiguous due to a disordered structure of the YSZ layer. A TEM-EDS analysis showed that there was only a reacted interface layer due to oxidation of the Si substrate. This means that a thin YSZ layer effects the passivation layer for the reduction of a thermodynamically unstable CeO2 layer against Si, as well as an epitaxy transmission from the Si substrate into the CeO2 layer.
View full abstractDownload PDF (1346K) -
Kazuhiko NAKANO, Kouichi TSUJI2006 Volume 55 Issue 6 Pages 427-432
Published: 2006
Released on J-STAGE: August 30, 2006
JOURNAL FREE ACCESSA new 3D-micro XRF instrument based on confocal set-up using two polycapillary X-ray lenses was developed and applied to rice-grain. The depth resolution of the confocal 3D-XRF spectrometer, which was evaluated by 10 μm thick Au foil, was approximately 90 μm. It was confirmed that the background intensity was reduced by applying polycapillary half lens. In the confocal set-up, 3D-elemental mapping of major elements in the rice grain was performed non-destructively at ambient air pressure. Two-dimensional elemental maps for K, Ca and Fe were obtained at different depths (200, 400 and 500 μm from the surface) in the embryo of the rice grain. Major elements, such as K, Ca and Fe, in the rice grain showed different mapping images in the different layers, respectively.
View full abstractDownload PDF (2133K) -
Masaaki HARADA, Masahiko SHOJI, Hiroshi KAWATA, Kenji SAKURAI2006 Volume 55 Issue 6 Pages 433-439
Published: 2006
Released on J-STAGE: August 30, 2006
JOURNAL FREE ACCESSThe high-energy X-ray fluorescence method has provided information of lanthanides in bulk samples without any interference of coexisting transition metals. In this study, the Kβ X-ray fluorescence spectra of Ce and Gd were measured with high-energy X-rays from a synchrotron-radiation source. The energy-dispersive spectra of Ce were measured with a Ge solid-state detector and analog/digital electronics for signal processing. It was shown that the intensities of the Kβ X-ray fluorescence spectra varied with the electronics used for signal processing and the experimental conditions (fluorescent intensity). This result should be noted for analytical applications using spectral intensities. To obtain higher energy-resolution spectra, a wavelength-dispersive measurement with a crystal monochromator and an imaging plate was also investigated. The five Kβ peaks of Gd (Kβ3, Kβ1, Kβ5, Kβ2, KO2,3) were separately observed with 70 keV X-ray excitation, and the energy resolution was estimated to be about 60 eV at Gd Kβ1 (48.7 keV) when the IP was read out with a 100 μm resolution. The energy resolution is yet to be improved by a higher resolution IP read-out or CCD camera system. It is expected that this high-energy X-ray fluorescence spectroscopy will be useful for the analysis of many kinds of lanthanide compounds and materials in the near future. Measurements of other lanthanide's Kβ spectra are now under investigation.
View full abstractDownload PDF (356K)
Technical Paper
-
Kouichi HAYASHI, Tetsutaro HAYASHI, Toetsu SHISHIDO, Eiichiro MATSUBAR ...2006 Volume 55 Issue 6 Pages 441-446
Published: 2006
Released on J-STAGE: August 30, 2006
JOURNAL FREE ACCESSAn X-ray excited optical luminescence phenomenon was used for atom resolved X-ray holography. In this study, we measured the incident-beam angular dependence of the X-ray luminescence intensity from a ZnO/MgO/Al2O3 film. The observed pattern corresponded to the hologram of an Al2O3 substrate, differently from the Zn Kα X-ray fluorescence hologram. This result shows the possibility of the hologram measurement of light elements whose X-ray fluorescence is hardly detectable in air.
View full abstractDownload PDF (571K)
Note
-
Pavel KARIMOV, Ernst Z. KURMAEV, Jun KAWAI2006 Volume 55 Issue 6 Pages 447-452
Published: 2006
Released on J-STAGE: August 30, 2006
JOURNAL FREE ACCESSA numerical simulation was performed to check the aptitude of low-Z materials, like carbon and boron, to be used as cladding layers in planar X-ray waveguides with a beryllium core. For a particular incident beam-energy value, an optimization technique based on a genetic algorithm was used to find the waveguide layer thicknesses, which provided the highest electric field intensity resonant enhancement in the core layer. The results of C/Be/C and B/Be/B waveguide simulations for incident beam energies from 10 to 15 keV were compared with the results obtained for Mo/Be/Mo waveguides. This comparison showed that waveguides with low-Z cladding layers should provide a guided beam of high intensity.
View full abstractDownload PDF (617K)
- |<
- <
- 1
- >
- >|