We present double-tracer autoradiography with 35S and 32P using imaging plates and an aluminum plate to visualize the individual distribution of sulfur and phosphorus in Brassica napus L.. Because of the different attenuation efficiencies of β-rays emitted from 35S and 32P, the specific image of 32P was taken when an aluminum plate was placed between the sample and the imaging plate. The specific image of 35S was obtained by subtracting the 32P image from the 35S and 32P image. It was observed that high amount of 35S was distributed at the edge of the leaves and in root tips. The 32P was distributed throughout the whole plant and it was found that the phosphorous amount was higher at the shoot apical meristems than those in leaves.
The effect of simultaneous exposure with filtered ultraviolet(UV)light and fluorescent(FL)light on unerasable latent images in imaging plates(IPs) was investigated by using three types of IP samples(BAS-TR, BAS-MS, and ST-VI). The IP samples were irradiated with 10MV and 80kV X-ray beams, ranging from 0.987Gy to 291Gy and 53.5μGy to 1.028Gy, respectively, and erased by repeating simultaneous exposure with both lights. All unerasable latent images were completely erased and reappearing PSL signals were not observed after the storage at 0°C for 20days. It was found that unerasable latent images in ST-VI samples needed the most rounds of exposure until they were erased completely because of protective layer and thicker phosphor. Unerasable latent images erased with FL light only were not erased completely and reappearing PSL signals were slightly observed after the storage at 0°C for 20days.
Time-course of oxygen stable isotopic ratios(i.e., δ18O)as well as annual or seasonal variation of δ18O has been examined to investigate the sources, the passing route and characteristics of precipitations in Niigata Prefecture. The precipitation samples have been mainly collected with a filtrating bulk sampler at the rooftop of Niigata University from 1999 to 2008. Furthermore, backward trajectories analyses have been also conducted for these samples taken sequentially for a short period. Consequently, the following features have been mainly clarified for the precipitations in Niigata Prefecture. (1)The δ18O values varied between −25.14‰ and −1.60‰, while the mean value of δ18O in each year was from −8.37‰(in 2006)to −7.33‰(in 2001). (2)As for the comparison among sampling points, the mean value of δ18O at seaside spots(i.e., Niigata City and Joetsu City)or marine spots(i.e., Sado City)is larger than that of inland spots(Shitada Village and Nagaoka City). (3)δ18O value was generally small in the rainy season, and relatively large in summer, and small in winter. (4)Decreasing δ18O content with time, as predicted by Rayleigh models of atmospheric vapor condensation, is a predominant feature of sequentially sampled rainfalls, particularly for precipitations taken during passage of typhoons.
The fundamental theory and technique of single crystal structure analysis using neutron are described in detail. As an example of simple compound, structure analysis of NaCl is shown, not only how to use conventional program but also how to solve by hand calculation. The method to get precise information for the crystal structure analysis is also given. At the end of the article, new method such like two-dimensional detector and pulse neutron methods are briefly described.
Neutron and X-ray diffraction methods were complementary applied for the structure analyses of the hydrogen-bonded dielectric materials 5-R-9-hydroxyphenalenon(R=methyl group, bromine; MeHPLN, BrHPLN, respectively). The nuclear and electron density distributions(NDD and EDD)in the materials are derived from the neutron and X-ray data, respectively. The comparison of the NDD and EDD revealed that the centers of the NDD and EDD of the hydrogen atom in the hydrogen bond differ from each other. This indicates the existence of a local dipole moment in the hydrogen atom, of which magnitude is comparable to the one in the typical ferroelectric material BaTiO3. The dipole moment in the hydrogen atom is disordered at room temperature because of the disorder of the hydrogen atom. The antiferroelectricity in MeHPLN at low temperature was found to be due to the antiferroic ordering of the dipole moment accompanied by the ordering of the hydrogen atom. Meanwhile the hydrogen atom in BrHPLN does not exhibit the orderings. The absence of the ordering is indicative of the tunneling motion of the hydrogen atom. The phase transition mechanisms of MeHPLN and BrHPLN were examined based on the tunneling model, using the experimentally obtained parameters. The calculation demonstrated that the phase diagrams of these materials can be well reproduced with this model.
Using neutron and resonant X-ray scattering, crystal structure and charge-ordering pattern in La1.5Ca0.5CoO4 was studied. Taking A2mm and Bm2m with a-b type twin structure into account, Co2+/Co3+ checkerboard charge ordering pattern was suggested in La1.5Ca0.5CoO4 by neutron scattering structure analysis. The charge ordering pattern and the valences of the two Co sites was clarified by a resonant X-ray scattering(RXS)measurement near the Co K-edge. We found a resonant signal at(3,0,0)reflection which corresponds to the charge ordering with a Co2+/Co3+ checkerboard pattern, and the Co valences of charge ordering were fully charge disproportionate.
Nucleosides and nucleotides, which are the basic components of nucleic acids, crystallize as hydrates. Numbers of crystal water molecules are a function of relative humidity surrounding crystals. Besides, phase transitions occur around 200K, which couple with the ordering of crystal water molecules. Neutron diffraction analysis on the humidity- and temperature-induced phase transitions of nucleotide hydrates was carried out. Neutron crystal structures showed that there were hydrogen-bonding networks common to nucleotide hydrates, switching of long-ranged hydrogen-bonding networks, and fluctuating crystal water molecules anchoring through hydrogen bonds.