Authors:R. Ozao, H. Yoshida, Y. Ichimura, T. Inada, and M. Ochiai
The thermal change of anodic alumina (AA), particularly the exothermic peak followed by the endothermic peak at ca 950C was
studied in detail by mainly using simultaneous TG-DTA/FTIR. The gradual loss of mass up to ca 910C is attributed to dehydration.
When heated at a constant rate by using TG-DTA, an exothermic peak with subsequent endothermic peak is observed at ca 950C,
but the exothermic peak becomes less distinct with decreasing heating rate. It has been found that gaseous SO2 accompanying a small amount of CO2 is mainly discharged at this stage. The reaction in this stage can be considered roughly in two schemes. The first scheme
can be said collectively as crystallization, in which the migration of S or C trapped inside the crystal lattice of the polycrystalline
phase (γ-, δ-, and θ-Al2O3, which presumably accompanies a large amount of amorphous or disordered phase) occurs. In the second scheme, the initial
polycrystalline (+amorphous) phase crystallizes into a quasi-crystallineγ-Al2O3-like metastable phase after amorphization. Conclusively,after the distinct exo- and endothermic reactions, the amorphous
phase crystallizes intoγ-Al2O3, presumably accompanying small amount of δ-Al2O3. It is also found that, when maintained isothermally, the metastable phases undergo transformation into the stable α-Al2O3 at 912C.
Authors:D. Ishii, T. Yamada, M. Nakagawa, T. Iyoda, and H. Yoshida
thermally induced structural transformation of a hydrogen-bonded crystal formed
from an amphoteric molecule of 6-[2-methoxy-4-(pyridylazo)phenoxy]hexanoic
acid MeO was studied using differential scanning calorimetry (DSC), Fourier
transform infrared spectroscopy (FTIR) and X-ray diffraction measurement (XRD).
Crystal form of the hydrogen-bonded crystal was measured by single crystal
four circle diffractometer (Mo-Kα radiation). As
a result, the crystal of MeO was stabilized by many C–H⋅⋅⋅O hydrogen
bonds, and the C–H⋅⋅⋅O hydrogen bonds were broken by thermal energy
reversibly. After transformation the supramolecular architecture was composed
of supramolecular polymer including free-rotation pentamethylene main chains.
Authors:M. Yoshida, S. Sumiya, H. Watanabe, and K. Tobita
A rapid separation method was developed for determination of low level promethium-147 and samarium-151. The rapid method, applied to environmental samples, provided speed and efficiency for the respective separation of Pm and Sm from other lanthanides with the simplified technique of high performance liquid chromatography (HPLC) system. The separation time of Pm and Sm in HPLC separation was shortened by stepwise eluent method of -hydroxyisobutyric acid as compared with a gradient eluent method of lactic acid with HPLC despite increase in sample volume for significant determination of Pm-147 and Sm-151. This method permitted the detection limit around 0.1 Bq/kg-dry-soil for Pm-147 and Sm-151 in 200 g soil sample by counting for 500 min with a liquid scintillation counter.
Authors:M. M. Fonseca, M. I. Yoshida, I. C. P. Fortes, and V. M. D. Pasa
Motor gasoline must present characteristics that guarantee its quality and the good performance of internal combustion engines without harming the environment. The contamination of gasoline by solvents can seriously adulterate its physical-chemical properties and affect its volatility and detonation capacity. To investigate organic solvent adulteration in gasoline samples, thermal analysis technique (TG/DTG) can be used as an auxiliary tool in the study of the thermal behavior of liquid fuels, as demonstrated by the present work involving a comparative analysis of kerosene-free and doped gasoline.
Authors:M. Yanaga, H. Wakasa, T. Yoshida, M. Iwama, K. Shinotsuka, M. Noguchi, and T. Omori
The behavior of Zn and other trace elements in mice fed with Zn-deficient diet during the growing period (Zn-dcf. mice) was investigated. A correlation between Zn concentration and Co concentration was found in the liver of Zn-def. mice. Two types of correlation between Zn and Mn concentrations were also recognised for the same livers. These facts suggest that Zn and Co, and also Mn are antagonistic, and that Co- and Mn-substitution for Zn-proteins and other Zn-bound compounds may occur, and/or the substituted compounds may be synthesized in the liver of Zn-def. mice.
Authors:M. Imamura, H. Nagai, M. Honda, K. Kobayashi, K. Yoshida, H. Yoshikawa, and T. Kobayashi
We present a brief description of the status of our accelerator mass spectrometry system at the tandem accelerator facility of the University of Tokyo and some examples of measurements in environmental samples which have been recently performed. Fallout10Be activities have been measured, from rain samples collected monthly in Tokyo from 1975 to 1977 and from 1984 to 1986, and compared with those of7Be and137Cs. A preliminary experiment on14C measurement in volcanic gas samples is also reported.
Authors:S. Seki, T. Aoyama, Y. Sawada, M. Ogawa, M. Sano, N. Miyabayashi, H. Yoshida, Y. Hoshi, M. Ide, and A. Shida
Tin-doped In2O3 (indium-tin-oxide) transparent conducting films are widely used as electrodes of liquid crystal displays and low-E windows.
In the present study, a systematic TDS study was undertaken for ITO films fabricated by various deposition processes; such
as PVD, dip coating and spray deposition. Water vapor was the main gas evolved from the films; gas evolution from the silicon
substrate was negligible. The evolution proceeded via two steps at approximately 373 and 473-623 K. The amount of the evolved
water was in the order: (dip-coated film)>(PVD films)> (spray-deposited film). This order was identical to that of the film's
Authors:L. Nagy, A. Szorcsik, H. Jankovics, T. Yamaguchi, K. Yoshida, M. Scopelliti, L. Pellerito, and E. Sletten
Complexes of adenosine and related compounds (adenosine-5’-monophosphate, adenosine-5’-triphosphate and pyridoxal-5-phosphate)
with Bu2SnO and/or BuSnCl2 were prepared in the solid state. The compositions of the complexes were determined by standard analytical methods. It was
found that the complexes contain the organotin(IV) moiety and the ligand in a ratio of 1:1. The FT-IR spectra demonstrated
that Bu2SnO reacts with the D-ribose moiety of the ligands, while Bu2SnCl2 is coordinated to the deprotonated phosphate group. The basic part of the ligands does not participate directly in complex
formation. Comparison of the experimental Mössbauer Δ (quadrupole splitting) values with those calculated on the basis of
the pqs concept revealed that the organotin(IV) moiety has Tbp and in some cases also Th geometry. The adenosine complex contains the organotin(IV) cation in two different surroundings (Tbp and Th). The local structures of the complexes were determined by means of EXAFS measurements. At the same time a number of organotin(IV)
complexes containing different organo moieties of calf thymus DNA were also prepared. Similarly as above, EXAFS data were
obtained for these compounds and analyzed by using multishell models up to 300 pm. These results are the first structural
data (bond lengths) on complexes formed with organotin(IV)-DNA and related compounds.
Authors:Y. Tabata, H. Kobayashi, M. Washio, Y. Yoshida, N. Hayashi, and S. Tagawa
A new picosecond pulse radiolysis Twin LINAC System has been constructed recently at Nuclear Engineering Research Laboratory at the University of Tokyo. The time resolution of the system is 20 ps and the system has a versatile capability for pulse radiolysis study. The outline of the facility is introduced. Some research carried out using the facility is presented. The examples are radiolysis of CCl4 and n-C21H44.
Authors:H. Yoshida, M. Yang, K. Masaka, Y. Houshito, K. Mashiko, and S. Nakamura
Phase transition behavior of polyesters derived from 2,7-phenanthrene dicarbonic acid diethylester and alkanediols with even
methylene carbon number was investigated by the simultaneous DSC-XRD method. The smectic A phase was observed on cooling from
the molten state. The transition entropy from the isotropic state to the smectic A phase was about 9.0 J mol-1 K-1, which depended on the methylene carbon number. The linear expansion coefficients, based on the (001) spacing of the crystalline
phase at room temperature, were 1.310-4 K-1 (crystalline phase), 5.710-4 K-1 (crystallization region), 1.710-3 K-1 (smectic A phase) during cooling, and 1.510-4 K-1 (crystalline phase), and 1.010-3K-1(melting region) on heating.