Naotake Morikawa

Influence of substituent groups in the arylation of substituted benzenes by aryl radicals derived from p-substituted N-nitrosoacetanilides

Abstract The partial rate factors for the homolytic arylation of substituted benzenes by substituted phenylradicals generated from p -substituted N-nitrosoacetanilides are presented, and the influence of a substituent is shown to be divided into two parts which are attributable to the inductive and the conjugative effect respectively. Hammetts relations hold for the partial rate factors for the arylations at the meta position. The correlation of the ϱ values with the inductive constants for the substituent groups in the arylating radicals indicates that the effect of a substituent in the radical is purely inductive in nature. The partial rate factors for arylations at the position para to a substituent in benzene are related to Hammetts substituent constant σ p by the equation: log (k p /k) = ϱσ p + τ p , where τ is a constant dependent on the nature of the substituent in the substrate and represents its conjugative capacity. On the assumption that the corresponding relation holds for the ortho position as well, very reasonable values of σ 0 and τ 0 are derived from the k 0 /k and ϱ values.

New upper bound on the electron anti-neutrino mass☆

A new upper bound ofmv < 13 eV at 95% CL has been obtained on the electron anti-neutrino mass. Thus results is based on a more than tenfold improvement in data relative to our previous measurements of the β-spectrum in 3H decay, and its in conflict with the finite mass of 17 <mv< 40 eV reported by an ITEP group

An Upper Limit for the Mass of the Electron Anti-neutrino From the Ins Experiment

Abstract The β-spectrum in 3 H decay has measured at INS with an energy resolution of 10–16 eV. The overall response function of the spectrometer system was reliably obtained with a reference 109 Cd source having the same chemical structure as the 3 H source. An upper limit of 32 eV has been obtained for the mass of the electron anti-neutrino with statistical and systematic errors.

Precise measurement of Ag KLL Auger-spectrum

Abstract The Ag KLL Auger spectrum has been measured with an energy resolution of 8 eV. The energies and the intensities of all nine lines are precisely determined with 1–2 orders of magnitude better accuracies than those in the previous experiment. The data obtained are found to be in good agreement with the theoretical calculations.

Measurements of the Production Cross Sections of Tritium from Oxygen Using p-Be and p-Li Neutrons up to En = 38 MeV

The production cross sections of tritium from oxygen have been measured in p-Be and p-Li neutron fields installed at the sectorfocusing (SF) cyclotron of the Institute for Nuclear Study (INS), University of Tokyo. Irradiations were performed with the semi-monoenergetic neutrons produced from the Be(p,n)B reaction at proton energies from 20 up to 40 MeV in 2.5-MeV steps, and those from Li(p,n)Be in 5-MeV steps with proton intensities of 2—5 μΑ, which yields neutron flux densities from 10 to 10 n/cm/sec at the position of sample irradiation. The neutron energy spectra were determined by an NE-213 scintillation counter. The tritium produced in the water used as the oxygen target was extracted by a distillation method, and measured by a liquid scintillation counter. The excitation functions for the 0(n,t)N reaction, measured by the p-Be and p-Li neutrons, agreed well with each other within the experimental uncertainties. The obtained results have been compared with the general trend in the (n,t) cross sections as a function of the atomic number of the target appearing in the literature.

Study of energy loss of 18 keV β-rays in a Langmuir-Blodgett thin film

Abstract The energy loss of 18 keV β-rays in a very thin Langmuir-Blodgett film of a chemical compound, arachidic acid, has been studied.

Neutrino Mass and End-Point Energy of ^3H β-Decay

The end-point energy of 3 H β-decay is re-examined and found as E 0 =18582.5±4.1 eV by a new measurement of the electron energy spectrum at INS. Also, an upper limit of the electron anti-neutrino mass is obtained as m ν <29 eV by combining with the result of a previous experiment.

Synthesis of186Re-DMSA and its biodistributions in mice

Optimum conditions were determined for high-yield synthesis of186Re- and188Re-meso-2, 3-dimercaptosuccinic acid complexes applicable to animal injection. The yield was more than 95% under the conditions used. The bone accumulation of the complexes was remarkable in the biodistributions in mice.

Precise measurement of Ag KLM and KLN Auger spectra

Abstract Ag KLM and KLN Auger spectra have been measured with a momentum resolution of 0.02%. With this resolution, most of the lines in these transitions are well separated and the complex spectral structure is revealed. Energies and intensities of these lines are precisely determined and compared with the results of the theoretical calculations.

Neutrino mass studied by measuring tritium beta-decay with an iron-free beta-ray spectrometer

Abstract The second measurement of the neutrino mass at INS has been carried out. Combining the new data with the result of the first measurement, a preliminary upper limit of 25 eV at the 95% confidence level has been obtained for the neutrino mass from only statistical consideration.