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New polymer gel dosimeters consisting of 2-hydroxyethyl methacrylate (HEMA), triethylene glycol monoethyl ether monomethacrylate (TGMEMA), polyethylene glycol 400 dimethacrylate (9G), tetrakis (hydroxymethyl) phosphonium chloride as an antioxidant, and gellan gum as a gel matrix were prepared. They were optically analyzed by measuring absorbance to evaluate a dose response. The absorbance of the polymer gel dosimeters that were exposed to 60Co γ-rays increased with increasing dose. The dosimeters comprising HEMA and 9G showed a linear increase in absorbance in the dose range from 0 to 10 Gy. The dose response depended on the 9G concentration. For others comprising HEMA, 9G and TGMEMA, the absorbance of the polymer gel dosimeters drastically increased above a certain dose, and then leveled off up to 10 Gy. The optical variations in these polymer gel dosimeters were also induced by x-irradiation from Cyberknife radiotherapy equipment. Furthermore, the exposed region of the latter polymer gel dosimeter exhibited a thermo-responsive behavior. [ABSTRACT FROM AUTHOR]

Superconducting and antiferroquadrupolar (AFQ) transitions in a Pr-based compound PrRh2Zn20 have been found to occur simultaneously at Tc = TQ = 0.06 K. The superconducting transition manifests itself by zero resistance and large diamagnetic susceptibility. The specific heat exhibits a Schottky anomaly peaking at 14 K, and magnetization curves measured at 2 K show anisotropic behaviors. The analysis of these data indicates that the crystalline electric field ground state ofthe trivalent Pr ion is the non-Kramers T3 doublet with the quadrupolar degrees of freedom. A sharp peak in the specific heat at 0.06 K has been attributed not to the superconducting transition but to the AFQ transition because the ordering temperature TQ decreases in B || [100] but increases in B || [110] and B || [11||] with increasing B up to 6 T. This anisotropic behavior of TQ(B) can be well explained by a two-sublattice mean-field calculation, which corroborates the AFQ ordered state below TQ. The entropy release at TQ is only 10% of R In 2 expected for the Γ3 doublet, suggesting possible interplay between the quadrupolar degrees of freedom and the superconductivity. [ABSTRACT FROM AUTHOR]

The density distribution of cold exciton clouds generated into a strain-induced potential well by two-photon excitation in Cu2O is studied at 2 K. We find that an anomalous spike, which can be interpreted as accumulation of the excitons into the ground state, emerges at the potential minimum. The accumulation can be due to stimulated scattering of cold excitons, mediated by acoustic phonon emission. The possibility of the formation of the thermodynamic Bose–Einstein condensate of paraexcitons is discussed. [Copyright &y& Elsevier]

Eight plants of the putative double monosomic addition line (DMAL, 2n =20) were developed by crossing a monosomic chromosome addition line of radish [f(A)-type monosomic addition line (MAL) (2n =19)] carrying the f chromosome of Brassica rapa (2n =20, AA) with another [e(C)-type MAL (2n =19)] having the echromosome of Brassica oleracea (2n =18, CC). The homoeological relationships between the two alien chromosomes were investigated by morphological, cytogenetic and random amplified polymorphic DNA (RAPD) analysis. Seventeen morphological traits that were not present in the radish cv. `Shogoin' were observed in both MALs and these traits were substantially exhibited in DMAL plants. At the first metaphase of pollen mother cells (PMCs), the two parental MALs showed a chromosome configuration of 9II + 1I, demonstrating impossibility of recombination between the R and the added chromosomes. The DMALs formed 10II in approximately 73% of PMCs, with one bivalent showing loose pairing between two chromosomes differing in size. In an attempt to identify the two MALs by RAPD-specific markers using 26 selected random primers, 13 and 20 bands were specific for the f(A)-type and the e(C)-type MALs, respectively; 12 bands were common to both MALs (26.7%). In conclusion, the f chromosome of B. rapa is homoeologous to the e chromosome of B. oleracea . The genetic domain (genes) for 17 morphological traits are linked to each homoeologous chromosome bearing 27% of the corresponding RAPD markers. [ABSTRACT FROM AUTHOR]

Epitaxial growth of CeO[sub 2](001) thin films on Si(001) substrates was achieved by electron beam evaporation. Reflection high-energy electron diffraction and cross-sectional high-resolution transmission electron microscopy established the formation of an epitaxial CeO[sub 2](001)/Si(001) structure with a cube-on-cube configuration. The epitaxial structure had to be formed at a temperature below 200 °C with a Si(001)-2x1, 1x2 reconstructed surface, and it could be formed even at room temperature. In order to improve the crystallinity, homoepitaxial growth conditions at a higher temperature with a high oxygen flow rate were also investigated. Homoepitaxy of ceria grown on a 5-nm-thick initial layer was demonstrated by θ/2θ-scan and φ-scan of x-ray diffraction. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A lower limit for the value of χ(3) associated with the two-photon resonance of the Γ1 biexcitons in CuCl at 1.6 K is found to be 5.4×10-5 esu. The upper bound of the two-photon resonance width is ΔE=0.02 meV. Broadening of the resonance occurs for light intensities I0>103 W/cm2. [ABSTRACT FROM AUTHOR]