New Members of the Pb-based 1222 Superconductor Containing Phosphorus: (Pb0.75P0.25)Sr2(Ln1.9?x Ce x Sr0.1)Cu2O z (Ln=Sm and Gd)

We previously reported on the synthesis of new Pb-based 1222 superconductor containing phosphorus in the (Pb_0.75P_0.25)Sr₂(Eu_1.9−x Ce _x Sr_0.1)Cu₂O _z system. Recently, we have discovered new members of the Pb-based 1222 superconductor containing phosphorus in the (Pb_0.75P_0.25)Sr₂(Ln_1.9−x Ce _x Sr_0.1)Cu₂O _z (Ln=Sm and Gd) systems. In each system, it is found that the samples of almost the single 1222 phase can be obtained for a wide composition area of 0.3≤x≤1.0. After annealing under 143 atm O₂ atmosphere at 400 °C, each sample of Ln=Sm and Gd with x=0.3 is found to show an onset of resistivity-drop at about 28 K and at about 24 K, respectively. Moreover, each samples of Ln=Sm and Gd is found to show an onset of diamagnetic signal at about 25 K and about 22 K, respectively. From these facts, these samples of Ln=Sm and Gd are found to be new members of the Pb-based 1222 superconductor containing phosphorus.     

Sodium Dodecylsulphate Electrophoretic Demonstration of Selective Adsorption of Gelatin Polypeptides on Silver Halide Particles-A Qualitative Examination

The gelatin fraction adsorbed on silver iodobromide particles was recovered by dissolution of the particles with sodium thiosulphate. The sodium dodecylsulphate, SDS, electrophoretic pattern of the recovered fraction was clearly different from that of the original gelatin. This is a direct indication of selective adsorption. Extraction of the adsorbed gelatin from the particles was examined with several reagents. Among them, the SDS extract gave a similar electrophoretic pattern to that of the fixation-recovered fraction. Electrophoretic patterns of SDS-extracted fractions from AgCl, AgBr and Agl particles indicate that the absorptions by these silver halides are selective and selectivity by each silver halide is different.     

Atomic-level modeling and computation of intergranular glassy film in high-purity Si3N4 ceramics

A model for intergranular glassy film (IGF) at grain boundaries in Si₃N₄ is proposed. The model agrees well with experimental information available. Although it has periodicity, atomistic simulations using the model enable to elucidate the rationale for the presence of the IGF. Amorphous models obtained by molecular dynamics based on the crystalline model enable atomistic simulations to address further issues related the IGF: it is found that the IGF plays an important role to relieve the strain due to misorientation of adjacent Si₃N₄ grains, that equilibrium IGF thickness is determined by the balance between the strain relief and energy penalty of silicon oxynitride constituting the IGF, and that both O and N are needed in the IGF to provide flexibility of networking structure of the IGF as well as to minimize chemical mismatch between adjacent Si₃N₄ grains and the IGF. Equilibrium IGF composition is successfully estimated for the first time.     

Development of Trityl Group Anchored Solubilizing Tags for Peptide and Protein Synthesis

Recently, solubilizing tag methods (Trt-K and Trt-R method) were developed for the challenging synthesis of peptides/proteins by means of native chemical ligation. In this system, the solubilizing tag can be attached to the Cys side chain by simply mixing the tag-introducing reagent under acidic conditions. The tagged peptides/proteins exhibited high water solubility thanks to the introduction of redundant oligo-Lys/Arg. In the final reaction, the tag can be quickly and cleanly detached by a standard deprotection reaction with trifluoroacetic acid. Herein, the development and application of these methods are described.     

Tangent Stiffness Equations for Laterally Distributed Loaded Members

Tangent stiffness equations for a beam-column, which is subjected to either uniformly or sinusoidally distributed lateral loads, are presented. The equations have been derived by differentiating the slope-deflection equations under axial forces for a member. Thus, the tangent stiffness equations take into consideration axial forces, bowing effect, and laterally distributed loads. As a numerical example, elastic buckling behavior of parallel chord latticed beams with laterally distributed loads is investigated to compare the results obtained from the present method with those from the conventional matrix method in which the distributed loads are considered as a series of concentrated loads at additional intermediate nodes of a member. Furthermore, buckling tests were carried out to confirm the equations derived as well as to clarify the buckling behavior of space frame structures. In conclusion, it can be said that the new equations can provide a good efficient way of estimating the equilibrium paths and buckling loads. They can also lead to a significant savings in core storage and computing time required for the analysis of space frame structures.     

New Pb-based 1212 Superconductor Containing Phosphorus, (Pb0.75P0.25)Sr2(Y1?xCax)Cu2Oz

New Pb-based 1212 compounds containing phosphorus have been discovered in the (Pb_1−y P _y )Sr₂(Y_1−x Ca _x )Cu₂O _z system; almost the single 1212 phase samples can be obtained for the composition range of 0.0≤x≤0.6 and y=0.25. The crystal structure for each sample has a tetragonal symmetry with the typical lattice parameters a=0.3828 nm and c=1.182 nm. Among them, the sample with x=0.6 and y=0.25 shows the onset of resistivity drop at about 39 K and zero-resistivity at about 17 K. Moreover, the sample shows a diamagnetic signal at about 38 K. These phenomena are found to originate from superconductivity with the bulk feature.     

In situ pressure calibration for piston cylinder cells via ruby fluorescence with fiber optics

A fiber-optic measurement technique is developed for estimating the pressure inside a piston cylinder cell up to approximately 4 GPa, based on the pressure-induced R1 fluorescence line shift of ruby (ruby scale). Ruby scale and a conventional technique (calibration on phase transitions of bismuth) were simultaneously applied to the cell filled with a pressure transmitting medium of isopropyl alcohol. The pressure readings of the two methods were consistent with each other, and no pressure gradient was observed. The ruby scale has the advantages of real time estimation and easy installation in a small space. Because of these advantages, three fibers were simultaneously introduced in the sample space at the same time, and pressure distribution was measured for Fluorinert (FC70:FC77=1:1), Daphne oil 7373, and Fomblin oil (YHVAC 13014).