Superconductivity in the tetragonal phase of La1.9Bi0.1CuO4+δ annealed under high oxygen pressure

We have investigated the relation between the crystal structure and superconductivity in La_1.9Bi_0.1CuO_4+δ , in which the phase separation observed in La₂CuO_4+δ is suppressed. A phase diagram in theT?δ plane is given for La_1.9Bi_0.1CuO_4+δ with excess oxygen. For very smallδ values, the crystal structure is orthorhombic, and an orthorhombic-tetragonal phase transition occurs markedly atδ ～ 0.03 in the measured temperature range between 13 and 293 K. Superconductivity is observed in the range of 0.04<δ<0.11. This is clear evidence thathigh-T _c superconductivity also appears in the tetragonal phase.     

The effect of gas atmospheres on resistivity of indium tin oxide films at high temperature

The effects of heat treatment in Q₂, O₂ and N₂, and Ar gases on the high temperature (500 C) electrical resistivity of indium tin oxide (ITO) film 52 nm thick prepared by chemical spray pyrolysis method were studied. The partial oxygen pressure effect on the resistivity was found to be to . The resistivity changes for cyclic exchange of O₂ by Ar gas at 500 C. These lead to the conclusion that chemisorption of oxygen atoms in the film surface is dominant for this thin film, for thicker films such as 640 nm oxygen diffusion is found to occur. The Langmuir model of the monolayer isothermal adsorption of oxygen atoms in the surface is applicable to the rapid change of resistivity.     

Effect of fiber array irregularities on microscopic interfacial normal stress states of transversely loaded UD-CFRP from viewpoint of failure initiation

A detailed investigation has been carried out to determine the effect of local fiber array irregularities and controlling fiber distribution parameters on microscopic interfacial normal stress states for transversely-loaded unidirectional carbon fiber (CF)/epoxy composites. Linear elastic finite element analyses were carried out for two-dimensional image-based models composed of about 70 fibers. The relationship between the geometrical distribution of two adjacent fibers and the interfacial normal stresses (INSs) is investigated for all fibers in different image-based models. Three boundary conditions for loading were selected: Case A involved cooling from the curing temperature (the difference in temperature was ?155 K); Case B involved transverse loading of 75 MPa chosen as an example of macroscopic transverse fracture strength; and Case C involved both cooling from the curing temperature and transverse loading of 75 MPa. High compressive INSs due to the difference in the coefficients of thermal expansion are observed at the location of the shortest interfiber distance for Case A (cooling). High tensile INSs are observed at the location of the shortest interfiber distance and where the fiber alignment angle to the loading direction is small for Case B (loading). For Case C (cooling and loading), the high thermal residual compressive INSs and the high mechanical tensile INSs compensate each other, and the INSs at a short interfiber distance are much lower than those for Case B. These results clearly indicate the importance of the contribution of the thermal residual stresses to the transverse tensile failure initiation of CF/epoxy laminates.     

Electrical properties of ferromagnetic Gd3−xS4 near its Curie temperature

Nonstoichiometric $\text{Gd}{}_{\mathrm{<mtext>3?</mtext><mtext>x</mtext>}}\text{S}{}_4\text{(0 <}\text{x}\text{<}\text{1}\text{3}\text{)}$, which exhibits a metallic behavior, was obtained by heating an insulating Gd₂S₃ at various temperatures under a vacuum. Electrical and magnetic properties of the samples obtained have been investigated from 4.2 K to 300 K. A maximum in resistivity was observed in the curve of resistivity vs. temperature. The temperature T_P, at which the maximum emerged, was very close to the Curie temperature T_C for the sample. An increase in resistivity at T_P, Δ_?, is proportional to ?_P exp ($\text{E}\text{k}{}_{\mathrm{B}}\text{T}{}_{\mathrm{P}}$), where ?_P is the resistivity obtained by the extrapolation from the linear portion to T_P in the ? vs. T curve. Using the relationship obtained, a model based on the formation of magnetic polaron was proposed for this system.     

Simulation of the fracture behavior of Zircaloy-4 cladding under reactivity-initiated accident conditions with a damage mechanics model combined with fuel performance codes FEMAXI-7 and RANNS

A continuum damage mechanics model using FEM calculations was proposed to be applied to an analysis of the fuel failure due to pellet cladding mechanical interaction (PCMI) under reactivity-initiated accident conditions. The model expressed ductile fracture via two processes: damage nucleation related to void nucleation and damage evolution related to void growth and linkage. The boundary conditions for the simulations were input from the fuel performance codes FEMAXI-7 and RANNS. The simulation made reasonable predictions for the cladding hoop strain at failure and reproduced the typical fracture behavior of the fuel cladding under the PCMI loading, characterized by a ductile shear zone in the inner region of the cladding wall. It was shown that occurrence of a through-wall crack is determined at an early stage of crack propagation, and the rest of the through-wall penetration process is achieved with a negligible increment in strain. The effect of a local temperature rise in the cladding inner region on the failure strain was found to be less than 5% for the conditions investigated. Failure strains predicted under a plane strain loading were smaller by 20%–30% than those predicted under equibiaxial tensions between the hoop and the axial directions.     

Detection of surface antigens on living cells through incorporation of immunorecognition into the distinct positioning of cells with positive and negative dielectrophoresis

Rapid determination of surface antigens on cells is possible by immobilization of cells accumulated by positive dielectrophoresis (p-DEP) via effective surface immunoreactions and removal of unbound cells by negative DEP (n-DEP). The DEP device for cell manipulation comprises a microfluidic channel with an upper indium tin oxide (ITO) electrode and a lower ITO microband array electrode (band electrode) modified with an antibody. Cells with the surface antigen introduced into the channel immediately accumulated on the surface of the band electrode during p-DEP generated by the application of ac voltage between the ITO electrode and the band electrode to immobilize by the specific antibody. The removal of accumulated cells to the gap region during n-DEP was used for rapid estimation of the residual cells with a specific surface antigen. We demonstrate here that human promyelocytic leukemia cells with the surface antigen CD33 can be captured on a band electrode modified with anti-CD33 antibody. The time required for the determination of the surface antigen using this compelled accumulation of cells by p-DEP and the separation of unbound cells by n-DEP is decreased to 60 s compared to that required by a cell binding assay using microtiter plates (30 min). Furthermore, the present method for a novel cell binding assay does not require pretreatment such as target labeling or washing of unbound cells and thereby enhancing throughput in the clinic and in cytobiology studies.     

Sensitive and spatially multiplexed detection system based on dielectrophoretic manipulation of DNA-encoded particles used as immunoreactions platform

In this work, we designed a new immunodevice that combines competitive immunoreactions on the microparticles, accumulation of these particles by negative dielectrophoresis (n-DEP), and their subsequent capture through hybridization among single-stranded DNAs (ssDNAs). Two widely used pesticides, atrazine and bromopropylate, were used as target molecules to test the resulting simultaneous detection system. For sensing, we prepared two different sets of microparticles: one modified with atrazine-conjugated bovine serum albumin (BSA-2d) and ssDNA-J1(up) and the other with bromopropylate-conjugated aminodextran (AD-155) and ssDNA-J2(up). The microparticles were incubated in a mixture of analyte-specific antibody and analyte at different concentrations to trap the unreacted antibodies prior to being labeled with antibodies conjugated with a fluorescence molecule. A suspension containing both types of microparticles was introduced into an n-DEP device consisting of an interdigitated microarray (IDA) electrode and channel modified with ssDNA-J1(down) and ssDNA-J2(down), which are complementary to ssDNA-J1(up) and ssDNA-J2(up), respectively. The n-DEP force generated by applying AC voltage to the IDA electrode displaced the microparticles toward the encoded areas, causing them to rapidly accumulate on the upper surfaces. Hybridization allowed us to distinguish the microparticles and sense multiple analytes by spatial recognition in the DNA-encoded areas. The fluorescence intensity of the captured particles, which depends on analyte concentrations, was measured selectively by focusing on specific areas. The strategy is advantageous for sensitivity due to the equivalent trapping efficiency by DNA hybridization and large surface area of the microparticle for immunoreactions. The rapidity and simplicity were still supported by particle manipulation. Using this concept, we detect atrazine and bromopropylate simultaneously with limits of detection (LODs) of 0.2 μg·L(-1), which covered the maximum residue level (MRL) in food samples established the European Union (EU) and Japan Ministry of Health, Labor and Welfare (MHLW).