[en] Electron spin resonance spectral studies on nonpolar hydrocarbons γ-irradiated at 4 and 77⁰K are reported. Trapped electron yields are tabulated. Results seem to indicate that relative trapped electron yields decrease with decreasing symmetricity of molecules

[en] Both higher corrosion resistance and paint adherence are given to films formed on the surfaces of metals by treating the surfaces with aqueous solutions of one or more materials selected from the group consisting of water soluble vinyl monomer or water soluble high polymer and then irradiating with ionizing radioactive rays on the nearly dried surface film. When a water soluble inorganic compound is mixed with the above mentioned aqueous solution, the film properties are greatly improved. The inorganic ionic material should contain a cation from the group consisting of Ca, Mg, Zn, Cr, Al, Fe, and Ni. Electron beams may be used. (U.S.)

[en] Poly(n-butylamino)(di-allylamino)phosphazenes were prepared by the reaction of (NPCL₂)_n with n-butylamine and di-allylamine. After the membranes were prepared by casting method, they were irradiated by UV, EB and ⁶⁰Co γ-ray. It was found from FTIR data that the CH double-bond CH₂/N-H ratios of the irradiated membranes were decreased with increasing doses. Also, the membrane did not dissolve in THF or other organic solvents. This supported that the CH double-bond CH₂ bond was cleaved by the irradiation and the cross-linking occurred between the intermolecular. Oxygen gas permeability values (D_k) of the irradiated membrane were determined with oxygen permeater and mechanical properties were determined with Tensilon. D_k values were decreased with increasing Young's modulus in the case of low concentration of di-allylamine

[en] Triggered by the experimental results of the MINIX, a computer simulation study was initiated on the nonlinear excitation of electrostatic electron cyclotron waves by a monochromatic electromagnetic wave such as the transmitted microwave in the MINIX. The model used assumes that both of the excited waves and exciting (pumping) electromagnetic wave as well as the idler electromagnetic wave propagate in the direction perpendicular to the external magnetic field. The simulation code used for this study was the one-and-two-half dimensional electromagnetic particle code named KEMPO. The simulation result shows the high power electromagnetic wave produces both the backscattered electromagnetic wave and electrostatic electron cyclotron waves as a result of nonlinear parametric instability. Detailed nonlinear microphysics related to the wave excitation is discussed in terms of the nonlinear wave-wave couplings and associated ponderomotive force produced by the high power electromagnetic waves. 2 references, 4 figures

[en] An innovative chemical separation process (ARTIST: Amide-based Radio-resources Treatment with Interim Storage of Transuranics) was proposed for the treatment of spent nuclear fuel. The main concept of ARTIST process is to recover and stock all actinides (An) and to dispose the fission products (FP). One of the main purposes of this process is selective isolation of uranium. Since the branched alkyl type N,N-dialkyl-monoamides (BAMA) have the steric hindrance on the complexation with metal cations, BAMA can be used to separate An(VI) from An(IV). N,N-di-(2-ethyl)hexyl-2,2-dimethyl-propanamide (D2EHDMPA) can recover U(VI) selectively without accumulating Pu(IV) in uranium isolation process. From extraction behavior of Np, D2EHDMPA can extract and separate U(VI) from Np(VI) without reduction from Np(VI) to Np(V) or Np(IV). (authors)

[en] This paper reports that one of the main characteristics of international coal trade in the 1980's was a much higher growth rate recorded in steam coal trade than in coking coal trade. Another was that coal import in Asia started to expand rapidly at the start of the 1980's. Increased coal imports by Asian countries is primarily attributed to growing steam coal imports. Steam coal accounted for more than two-thirds of the additional coal imports by Asian countries between 1980 and 1988. Nonetheless, coking coal still forms the largest segment of Pacific coal trade. Only in the early 1990's is steam coal trade expected to exceed coking coal trade in the Pacific

[en] The layered compound La_2-2xSr_1+2xMn₂O₇ (x=0.3) consists of bilayers of metallic MnO₂ sheets separated by insulating material. The compound exhibits markedly anisotropic magnetoresistance at temperatures well below the three-dimensional magnetic ordering temperature T_c=90 K in addition to colossal magnetoresistance around T_c. We present neutron diffraction data which show that the magnetic structure of this material switches from antiferromagnetic stacking of the (ferromagnetically ordered) sheets in zero field to ferromagnetic stacking in a field of 1.5 Tesla. The data are the first to be collected on any manganite as a function of applied field, exactly as the magnetoresistance data themselves are collected. They provide a natural explanation of the low-field magnetoresistance in the ordered phase in terms of spin-polarised tunnelling between the magnetic layers and suggest that the material is a bulk stack of spin-valve devices. (author)

[en] Luminescence lifetime and intensity measurements of lanthanide(III) ions, Ln³⁺ (Eu, Gd and Tb), in non-aqueous solutions containing azide ions (N₃^-) have been performed to study the quenching effect of N₃^- using time-resolved laser-induced luminescence spectroscopy and conventional luminescence spectroscopy. The luminescence Stern-Volmer quenching constants K_sv^PHI and azide non-radiative decay constants k_N3 of the excited Eu(III) ion in the presence of N₃^- were measured in N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylformamide (NMF), formamide (FA) and methanol (MeOH). The obtained quenching effect of the Ln³⁺ luminescence by azide in the non-aqueous solvents shows the order: Gd>Eu>Tb, which does not obey the energy gap law, ΔE, between the emitting and the ground state of the Ln³⁺ ion (Gd>Tb>Eu). The anomaly in the quenching pattern observed in the case of Eu³⁺ can be attributed to its partial reduction to Eu²⁺, additionally to the energy transfer from excited state of Eu³⁺ to N₃^-. The values of quenching rate constants k_N3measured for Eu³⁺ in various solutions depend on the acceptor number (AN) of the solvents used

[en] Total recovery of TRU from nitric acid solution was studied by using TODGA whose extractant is a tridentate ligand showing the high extractability for An(III) and An(IV). TODGA extracts Pu(IV), Am(III) and Cm(III) effectively but not Np(V), therefore Np(V) has to be reduced to Np(IV) prior to extraction. From the results of the extraction of fission products, Sr(II), Zr(IV) and lanthanides(III) give high distribution ratios in TODGA-HNO₃ system. After extraction of TRU with Sr(II) and Zr(IV), these FP elements can be stripped by using 0.2 M oxalic acid in 2 M HNO₃ or diluted HNO₃, while TRU remains in the organic phase. After separation of Sr(II) and Zr(IV), the backward extraction of total TRU into aqueous phase was also studied. (authors)

[en] DNA is able to take a number of local conformations. (CG) n repeats have the highest potential to Z-DNA which has a left-handed zig-zag backbone and unusual syn-conformation purine base. Because of the polymorphic nature of dinucleotide repeats, it seems possible that Z-DNA forming sequences may provide a source of genetic variation if they occur in regions that are important for the regulation of gene activity. Here, we investigated structural properties of Z-DNA compared with those of B-DNA with respects to one-electron attachment reaction of 8-bromodeoxyguanosine (dBrG) and fluorescence properties of 2-aminopurine (Ap). To investigate one-electron attachment reaction of Z-DNA, we synthesized oligodeoxynucleotides modified by dBrG in which syn-conformation deoxyguanosine was stabilized by steric repulsion between 8-bromo group of dBrG and sugar moiety in Z-DNA. Debromination from the dBrG modified oligodeoxynucleotides occurred from the one-electron attachment during the gamma-ray irradiation. The structural dependence of B- and Z-DNA was observed in the one-electron attachment reaction. Interestingly, the higher conversion of dBrG were observed in the Z-DNA than in the B-DNA. Since the solvent accessibility to purine base in Z-DNA increases compared with that in B-DNA, it is suggested that the electron attachment is enhanced in Z-DNA than in B-DNA. Next we studied the fluorescence properties of Ap in left-handed Z-DNA and compared with those in B-DNA. Since photoexcited adenine analogue Ap can serve as a sensitive probe of DNA structural dynamics, we synthesized Ap- and dBrG-modified oligodeoxynucleotides. Higher intensity was observed in the steady-state fluorescence of Ap in Z-DNA than in B-DNA. A new peak at 275 nm was observed in the excitation spectrum measured at the Ap emission wavelength 370 nm in Z-DNA. This has been explained by the energy transfer from the excited nucleobases to Ap. It is found that Ap is a useful fluorescence probe of Z-DNA