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Journal of Thermal Analysis and Calorimetry
Authors:
T. Tanaka
,
J. Magoshi
,
Y. Magoshi
,
S. ichi Inoue
,
M. Kobayashi
,
H. Tsuda
,
M. Becker
, and
Sh. Nakamura

Abstract  

The thermal properties of liquid silk from domestic and wild silkworms are investigated. Liquid silks obtained from the silk gland of the domesticated silkworm, Bombyx mori and four wild silkworms, Samia cynthia ricini, Dictyoploca japonica, Antheraea pernyi and Antheraea yamamai were used. The DSC curves for the liquid silk from the domestic silkworm have weak endothermic peaks corresponding to the breaking of hydrogen bonds in the β-form or to the untangling of physical network. The DSC curves for the wild silkworm silks, however, show clear exothermic peaks corresponding to a phase transition from the α-helix conformation to the β-form. Liquid silk from all the different silkworms undergoes a characteristic irreversible phase transition.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
K. Kobayashi
,
M. Kuwano
,
K. Sueki
,
K. Kikuchi
,
Y. Achiba
,
H. Nakahara
,
N. Kananishi
,
M. Watanabe
, and
K. Tomura

Abstract  

Advantages and uniqueness of radiochemical techniques in fullerene studies are pointed out. Some experimental data are presented on metallofullerenes production yields, HPLC elution behaviors of Y, La, Gd containing fullerenes, encapsulation of a new metal in the carbon cage, stability of the carbon cage against recoil energy, and the distribution of metallofullerenes among various organs of rats.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
N. Shigeta
,
H. Matsuoka
,
A. Osa
,
M. Koizumi
,
M. Izumo
,
K. Kobayashi
,
K. Hashimoto
,
T. Sekine
, and
R. Lambrecht

Abstract  

No-Carrier-Added186Re was produced using the186W(p,n)186Re nuclear reaction with 13.6 MeV protons on thick targets of 99.79% isotopically enriched186WO3. The theoretical excitation functions for producing186Re, and possible radionuclidic impurities of182Re,183Re, and184Re were calculated using the ALICE code. Cross-sections of the186W(p,n)186Re reaction were measured up to 20 MeV using the stacked target method with thin foils of natural composition tungsten metal. The experimental and theoretical excitation functions were in good agreement. Targetry used at the TIARA cyclotron, and a radiochemical separation scheme for186Re are described.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
S. Ambe
,
S. Chen
,
Y. Ohkubo
,
Y. Kobayashi
,
H. Maeda
,
M. Iwamoto
,
M. Yanokura
,
N. Takematsu
, and
F. Ambe

Abstract  

We established Multitracer, a new versatile radiotracer technique, for simultaneous tracing of a number of elements in various chemical, environmental, and biological systems. Metal foil targets (typically Au, Ag, Ge, Cu and Fe) are irradiated with C, N, or O ions accelerated up to 135 MeV/nucleon by RIKEN Ring Cyclotron. Radiochemical procedures have been developed to remove the target material leaving the nuclides as Multitracer solutions containing various radionuclides of Be, Na, Mg, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Te, I, Ba, Ce, Pm, Eu, Gd, Tb, Tm, Yb, Lu, Hf, W, Re, Os, Ir, Pt, and Hg. Multitracers enable efficient tracing of a number of elements, and comparison of their behavior under strictly identical experimental conditions. Such features will be demonstrated by means of an example of application to a model experiment for the study of removal mechanism of various elements from the ocean.

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Abstract  

To determine the cross sections of the135Cs(n,γ)136Cs reaction, a sample of135Cs included in a “standardized solution” of137Cs was used as a target and irradiated in a reactor. The ratio of the atom number of135Cs to that of137Cs was determined to be 0.89±0.03 with a quadrupole mass spectrometer. The thermal cross section and the resonance integral measured in this study were determined to be 8.3±0.3 and 38.1±2.6 b respectively.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
Y. Kobayashi
,
Y. Tsuruoka
,
M. Kubo
,
H. Nonaka
,
Y. Yamada
,
Y. Sakai
,
H. Shoji
,
W. Sato
,
A. Shinohara
,
Y. Watanabe
, and
H. Matsue

Abstract  

In order to investigate the physical and chemical effects of neutron capture reaction, a neutron in-beam Mössbauer spectroscopic study on two isomorphs of iron disulfide: pyrite and marcasite, were carried out with a parallel plate avalanche counter at room temperature. In both compounds only two major products accounted for the obtained spectrum: one with Mössbauer parameters close to the parent compound and the other one considered to be a new product. The yield of the parent-like species was different in the two isomorphs.

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Abstract  

Quantitative determination of ppb-order 10B was carried out in a small number of cultured tumor cells by particle tracks by the 10B(n,)7Li reactions using solid state nuclear track detector (SSNTD) for boron neutron capture therapy research. The detection limit of 10B concentration in tumor cells is less than 1·10-3 ppm under our experimental conditions which permits the quantitative determination of 10B in a small number of boronated tumor cells (105/ml = ca. 0.1 mg). Boron quantities in tumor cells determined were well compatible with the tumor cell killing effects of boron neutron capture therapy.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
Y Kobayashi
,
M. Kubo
,
Y. Yamada
,
T. Saito
,
H. Ueno
,
H. Ogawa
,
W. Sato
,
K. Yoneda
,
H. Watanabe
,
N. Imai
,
H. Miyoshi
, and
K. Asahi

Abstract  

In-beam Mössbauer spectra of 57Fe, decayed from short-lived 57Mn (T1/2 = 1.45 min) implanted into potassium permanganate, KMnO4, were measured at temperatures between 11 K and 130 K. This is the first application of a secondary RI beam to the study of valence states after nuclear transformation. The in-beam Mössbauer spectra obtained below 90 K could be analyzed with two components, a doublet and a singlet. From the calculations of the molecular orbital wave functions, the singlet is suggested to be substitutional 57Fe atoms for Mn-sites in tetrahedral [MnO4] with an unusually high valence state of Fe8+.

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Journal of Thermal Analysis and Calorimetry
Authors:
M. Wang
,
Y. Sawada
,
K. Saito
,
S. Horie
,
T. Uchida
,
M. Ohtsuka
,
S. Seki
,
S. Kobayashi
,
T. Arii
,
A. Kishi
,
T. Takahashi
,
Y. Nishimoto
,
T. Wakimoto
,
K. Monzen
,
I. Kashima
,
T. Nishikiori
,
L. Sun
, and
R. Ozao

Abstract  

The thermal change of the tris(8-hydroxyquinolinato)aluminum (Alq3) is currently investigated by XRD-DSC and TG. The phase transition of Alq3 from α-phase to γ-phase takes place at 643–669 K. A very sharp peak with the peak temperature at approx. 709 K is ascribed to the melting of the Alq3. The decomposition of the Alq3 was observed accompanied with the melting and evaporation at >703K. The effect of the atmospheres on the mass loss procedure was studied by TG. It was found that thermal process of Alq3 was strongly influenced by the partial pressure of water vapor in the atmosphere instead of oxygen.

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