Effects of ground-state correlations on 2νββ decay rates and limitations of the QRPA approach

Half-lives of the 2νββ decay are calculated in the proton-neutron QRPA for⁷⁶Ge,⁸²Se,¹⁰⁰Mo,^128,130Te,¹³⁶Xe and¹⁵⁰Nd. The strength of the particle-particle interaction, which plays a decisive role for a reliable evaluation of the half-lives, is determined from a QRPA calculation of singleβ ⁺ decays. The 2ν decay rates calculated with the interaction strength fitted in this way are strongly suppressed and found to be consistent with the existing experimental data. Effects of the ground-state correlations on the suppression are investigated. On the other hand, the present calculation indicates limitations of the QRPA approach.     

DNA cleavage induced by thermal electron transfer from a dimeric NADH analogue to acridinium ions in the presence of oxygen

Acridinium ions, which can intercalate to DNA, act as thermal DNA cleavers in the presence of a dimeric NADH analogue and O2 in an aqueous solution via thermal electron transfer from a dimeric NADH analogue to acridinium ions, followed by the electron-transfer reduction of O2 to O2*- by the resulting NAD radicals.     

Initial mode of radical pair formation in n-hydrocarbons irradiated at 1.5 and 4.2 K

The ESR spectra of X-irradiated (at 1.5 and 4.2 K) single crystals of n-decane-d₂₂, n-decane-h₂₂ and their mixtures have been measured at 1.5 and 4.2 K. It is concluded that almost all alkyl radicals are inherently formed in pairs in a fairly random fashion and that the spacial distribution of the radicals depends on the irradiation temperatures. In the crystal of n-decane-d₂₂, a 1,3-carbon intrachain radical pair is identified together with a number of very close interchain pairs which are formed between almost all kinds of the first neighboring chains. The crystal of n-decane-h₂₂ gives considerably larger spacial distribution of radicals, indicating a remarkable mass effect on the radical pair formation.     

Determination of urea by ion chromatography with an immobilized urease reactor

An immobilized urease reactor can be used with ion chromatography for the simultaneous determination of urea, and sodium, potassium and ammonium ions. The conversion of urea to ammonium ion was found to be 76.5%. The calibration graph for urea was linear over the range 1 × 10^?5?1 × 10^?3 M (RSD 3%). The method was applied to human urine and a chemical fertilizer.     

Fluorescence maxima of 10-methylacridone-metal ion salt complexes: a convenient and quantitative measure of lewis acidity of metal ion salts

Aromatic carbonyl compounds such as 10-methylacridone form the Lewis acid complexes including paramagnetic and redox active Lewis acids. The fluorescence energies of the Lewis acid complexes are well correlated with the O2*--Lewis acid complexes derived from the gzz-values of the ESR spectra of the superoxide anion-Lewis acid complexes, thus providing a quantitative measure of the Lewis acidity.     

Improving the properties of the proton exchange membranes by introducing α-methylstyrene in the pre-irradiation induced graft polymerization

New proton exchange membranes (PEMs) were prepared by pre-irradiation induced grafting of α-methylstyrene (AMS)/styrene (STY)/divinylbenzene (DVB) into the crosslinked polytetrafluoroethylene (RX-PTFE) films and successively sulfonated. The new PEMs showed the improved glass transition temperature and chemical stability as compared with the PEMs prepared by pre-irradiation induced grafting of STY/DVB. The balance of the cost, grafting kinetic, thermal properties and the properties of the resulted proton exchange membrane is the key point of this work.     

Magnetic properties of Pm in PrNi

A magnetic property of Pm as an impurity in PrNi single crystal was investigated by means of the low-temperature nuclear orientation of^143,144Pm. The angular distribution of -ray anisotropies revealed that the direction of hyperfine field experienced by the nuclei lie in the (a, c) plane andmade an angle of 60° (5) or 240° (5) with respect to the crystallinec-axis. From the temperature dependence of the anisotropies the strength of the hyperfine field of Pm in PrNi was deduced to be 185(22)T. The hyperfine field of Co at the Ni site of PrNi was found to be less than 4T.