RADIOISOTOPES

Determination of ²³⁵U/²³⁸U Isotopic Ratio by Neutron Activation

Hiroyuki YOSHIDA, Chushiro YONEZAWA

1970Volume 19Issue 2 Pages 73-76
Published: February 15, 1970
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.19.2_73

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A method determining ²³⁵U/²³⁸U isotopic ratio in small uranium samples by neutron activation is described. The sample containing 1-10 μg of uranium is irradiated in a reactor for 20 minutes. After cooling for 24 hours, the sample is dissolved into 25 ml of 1N hydrochloric acid. For the determination of ²³⁵U, 10 ml of the solution is taken and ⁹⁹Mo is separated by means of solvent extraction with α-benzoinoxime. For the determination of ²³⁸U, another 10 ml of the solution is taken and ²³⁹Np which is formed by ²³⁸U (n, γ) ²³⁹Uβ→²³⁹Np reaction is separated by solvent extraction with thenoyltrifluoroacetone. Both radioactivities are measured with an NaI (T1) scintillation counter, and ²³⁵U/²³⁸U isotopic ratio is calculated from ⁹⁹Mo/²³⁹Np radioactivity ratio.
Ten analyses of 10.10% ²³⁵U samples containing 10 μg of uranium gave a relative standard deviation of 3.9%.

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Formation of Amino Acids from Aqueous Mixtures of α-Keto Acids and Ammonia by γ-lrradiation

Kimiko MASUDA, Tokan RAI, Mutsuaki SHINAGAWA

1970Volume 19Issue 2 Pages 77-80
Published: February 15, 1970
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.19.2_77

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The formation of amino acids from several α-keto acids by γ-irradiation in aqueous ammonia solution was investigated. The yield of every amino acid was studied as a function of radiation dose as well as of concentrations of α-keto acid and ammonia. The reaction process was proposed as the reductive amination of α-keto acids induced by irradiation. On the amination of pyruvic acid alanine was formed (G=0.75) . In the amination of phenylpyruvic acid phenylalanine was obtained (G=0.5) . The amination of α-keto-isovaleric acid and α-keto-isocapronic acid leads to the formation of varine (G=0.84) and leucine (G=0.68), respectively. Tryptophan was found as the corresponding amino acid by amination of indolpyruvic acid (G=0.45) .

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Radiation Graft Copolymerization of Acrylamide on Polyolefines

Kiyoshi HAYAKAWA, Kaoru KAWASE, Hiromi YAMAKITA

1970Volume 19Issue 2 Pages 81-86
Published: February 15, 1970
Released on J-STAGE: September 07, 2010

DOIhttps://doi.org/10.3769/radioisotopes.19.2_81

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Several techniques of grafting applicable to the polyolefines-acrylamide system were examined. In the simultaneous irradiation technique in acetone solution of acrylamide most of the monomer was consumed in the homopolymerization and the efficiency of grafting was very low. The low-temperature preirradiation technique brought about a high extent of grafting without homopolymer formation. The vapor-phase simultaneous irradiation technique using the sublimation vapor was applicable to the polyolefines either by γ-rays or by ultra-violet-rays, but much higher dose was required in this technique than in the simultaneous irradiation grafting in solution. It was also possible to graft-copolymerize by the preirradiation technique using sublimation vapor, but the extent of grafting was very low. The compositions of the grafted products were also examined in several instances.

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Autoradiography of Boron

Jun-ichi Kawamoto, Masago Yamamoto

1970Volume 19Issue 2 Pages 87-88
Published: February 15, 1970
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.19.2_87

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Radiolysis of Ascorbic Acid in Aqueous Solution

Hajime OGURA, Moriyasu MURATA, Masaharu KONDO

1970Volume 19Issue 2 Pages 89-91
Published: February 15, 1970
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.19.2_89

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[title in Japanese]

[in Japanese]

1970Volume 19Issue 2 Pages 92-101
Published: February 15, 1970
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.19.2_92

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[title in Japanese]

[in Japanese]

1970Volume 19Issue 2 Pages 102-107
Published: February 15, 1970
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.19.2_102

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[title in Japanese]

[in Japanese], [in Japanese]

1970Volume 19Issue 2 Pages 108-121
Published: February 15, 1970
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.19.2_108

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[title in Japanese]

1970Volume 19Issue 2 Pages A1027-A592
Published: February 15, 1970
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.19.2_A1027

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