RADIOISOTOPES

Reactivity of Normal Chain Diamines in the T-for-H Exchange Reaction

Hiroshi IMAIZUMI, Hiroyoshi SAITO, Naoki KANO

2006Volume 55Issue 4 Pages 183-190
Published: April 15, 2006
Released on J-STAGE: March 01, 2011

DOIhttps://doi.org/10.3769/radioisotopes.55.183

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The hydrogen-isotope exchange reaction (T-for-H exchange reaction) between tritium-labeled poly (vinyl alcohol ) and each normal chain diamine has been observed in the range of 50 to 90°C. Consequently, the activity of the diamine increased with increasing reaction time. Applying the A″-McKay plot method to the observed data thus obtained, the rate constants (k) for the diamines were also obtained. Using each k thus obtained, the relation between the number of methylene groups in the diamine and the reactivity of the diamine was quantitatively compared.
Then, in order to clarify the effect of relative atomic charge of N atom in the amino group on the reactivity of the diamine, the MOPAC method was used. From both the above-mentioned and the obtained previously, the following five items were found as to normal chain amines in the T-for-H exchange reaction. (1) Increasing the number of methylene groups in each diamine leads to decreasing k for the diamine. (2) The decreasing ratio of the reactivity of the diamine, where the number of methylene groups in each diamine increases from one to three (and to five), is larger than the decreasing ratio of the reactivity of the diamine, where the number of the methylene groups in the diamine increases from two to four (and to six) . (3) The effect of temperature on the reactivity of several compounds is in the following order: (dicarboxylic acids) < (diamines) < (diols) < (aromatic compounds) . (4) When the number of methylene groups is odd, the relative atomic charge of the N atom in the amino group decreases with increasing number of methylene groups in the diamine. When the number of methylene groups is even, the relative atomic charge of the N atom has a tendency to increase with increasing number. (5) We have a high possibility that the structure of normal chain diamine in a certain solvent may be stereo-chemically estimated by applying both the MOPAC method and the method used in this work.

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New Automatic Condensation System for Fallout Measurement

Masaaki SAITO, Norio KATO

2006Volume 55Issue 4 Pages 191-196
Published: April 15, 2006
Released on J-STAGE: March 01, 2011

DOIhttps://doi.org/10.3769/radioisotopes.55.191

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A continuous evaporation system was developed. Sample water was continuously supplied to rotary evaporator with a tube pump. The tube pump was controlled by water level sensor placed in a sample flask. Condenser was turned upside down, and droplets of water were removed by an aspirator. The merits of the system are as follows, (1) labor saving, (2) no generation of water vapor in a room, (3) fire prevention, (4) 20 L of sample water per day can be evaporated.

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Concentration Factors of Marine Products for Transuranic Nuclides

Masanao NAKANO, Masanori TAKEYASU, Hiroki FUJITA, MINORU TAKEISHI

2006Volume 55Issue 4 Pages 197-203
Published: April 15, 2006
Released on J-STAGE: March 01, 2011

DOIhttps://doi.org/10.3769/radioisotopes.55.197

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From the measurement result of the^{239, 240}Pu and ²⁴¹Am concentration in marine products collected offshore Tokai-mura from 1987 to 2004, the concentration factors (CFs) for Pu and Am were calculated and compared with the past CFs. The present CFs of flatfish, shellfish and brown algae for Pu were larger, comparing with the CFs obtained about 20 years ago. It is suggested that the transfer of radionuclide to these bottom marine products from bait, sediment and its interstitial water would play more important role than that from surface seawater in case of depletion of their concentration in seawater.
The CFs for Cm and Np were tentatively estimated from the knowledge and foreign data, since there is very few data offshore Tokai-mura or around Japan.

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Dynamics of Radioactive Lead Isotopes in the Global Environmental Atmosphere

Yuya KOIKE, Toshiso KOSAKO

2006Volume 55Issue 4 Pages 205-215
Published: April 15, 2006
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.55.205

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I. Changing from National Personnel Authority Rules to Ordinance on Prevention of Ionizing Radiation Hazards (On Turning National Universities into Independent Administrative Entities)

Kiyoshi NOMURA

2006Volume 55Issue 4 Pages 217-220
Published: April 15, 2006
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.55.217

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II. Present Status of Measurement Methods and Practical Examples

Yoshiaki HITOMI

2006Volume 55Issue 4 Pages 221-229
Published: April 15, 2006
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.55.221

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Present Status and Prospects of Ultralow Level Radioactivity Measurements. Introduction to the Series

Technical Committee of Ultralow Level, Kazuhisa KOMURA

2006Volume 55Issue 4 Pages 231-232
Published: April 15, 2006
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.55.231

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Present Status and Prospects of Ultralow Level Radioactivity Measurements (1) . Fundamentals of Low Level and Ultralow Level Radioactivity Measurements

Kazuhisa KOMURA

2006Volume 55Issue 4 Pages 233-243
Published: April 15, 2006
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.55.233

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ERRATUM

2006Volume 55Issue 4 Pages 245
Published: 2006
Released on J-STAGE: July 21, 2010

DOIhttps://doi.org/10.3769/radioisotopes.55.4_245

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