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The results of two test methods were compared among three laboratories to determine a standard measurement method of critical current (Ic) as a function of bending strain for Ag-sheathed Bi-2223 superconductors. The VAMAS round-robin-test method (RRT) and the bending-rig method developed by Goldacker were used. The Icdegradation started with less bending strain for RRT than for bending-rig. Average irreversible strains (?irr) were 0.30% for RRT and 0.37% for bending-rig. Another test identified parameters that affected the results. A modified RRT method, with a current connection between the sample and the electrode, was used to avoid some thermal stresses of the test procedure. The ?irrvalues increased to the level of the bending-rig, but the modified RRT Icdegradation rate with bending strain was higher. The stress states during sample bending differed between these methods. The shear stress was examined as a source of the Icdegradation rate differences with strain in terms of the crack propagation and delamination defects of oxide filaments from the Ag sheath.

When an upward magnetization force Fm is imposed on a liquid, the force acting on the liquid is the difference between the gravitational and magnetization forces. Thus, the magnitude of vertical acceleration acting on the liquid can be varied from 1 g to 0 g by changing the upward Fm. To verify this vertical acceleration‐control method, behavior of bubbles formed by injecting gas from a nozzle was examined. By decreasing the magnitude of vertical acceleration, the number of bubbles formed per unit time decreased and their size increased. These results confirm that vertical acceleration can be changed from normal gravity to near‐zero gravity. The method to generate low‐gravity conditions will find many applications over a wide range of research.

AbstractLiquid crystalline polythiophene (LC-PTs) and polythienylenevinylene (LC-PTVs) derivatives with various length of methylene spacer in the LC substituents were synthesized. LC-PTs were prepared through dehalogenative polycondensation using Ni(0) complex, and LC-PTVs through Stille reaction followed by Heck reaction. The polymers showed enantiotropic smectic phase. Both LC-PTs and LC-PTVs were fluorescent with greenish yellow and/or green colors. The polymers were macroscopically aligned under magnetic field of 10 Tesla. Alignment of the polymers was confirmed by polarizing optical microscope, X-ray diffraction and polarized infrared spectra. The aligned polymers showed not only anisotropic electrical conductivity but also dichroic fluorescence. It is found that the LC conjugated polymers synthesized here are promising materials with linearly polarized luminescence.

For the data of the limiting viscosity number of poly(2-vinylpyridine) of a low molecular weight Mw=2.26–0.21×104in benzene and methanol, the value of the thickness parameter, b, and the energy difference, E, between the gauche and trans state were discussed in terms of the theory of Rossi and Perico. It is possible to use this theory for the viscosity data in the molecular weight range of 0.35–1.30×104. The values of Eand bwere thus estimated; Edepended on the nature of the solvent for this polymer, while bwas constant (0.3 nm). The temperature dependence of the calculated limiting viscosity number, dln[η]⁄dT, in benzene and dioxane was discussed, together with the measured values.

The compositional dependence of the columnar grain structure in Fe1-x-Cox(x=0-1) films has been investigated. The films were vapor-deposited at an incidence angle of 65° on glass substrates kept at 473 K. The pressure during deposition was 2.7×10-2Pa. Reflection ellipsometry detected morphology changes at compositions of 0.02, 0.5, 0.77 and 0.9. The X-ray analysis and replica electron microscopy revealed that these four compositions correspond to the crystallographic changes. With increasing x, columnar grains change texture from type I [111] (10) to [100] (010) at x=0.5 and the crystal structure from bcc to hcp at x=0.9; in the xrange from 0.02 to 0.77 columnar grains clearly exhibit the crystal habit. On the basis of these results the crystallographic contribution to the formation of the columnar grain structure is discussed.

In order to establish the crystallographic contribution to the formation of the columnar grain structure we investigated two characteristics of the columnar grain structure (inclination and bundling of columnar grains) and the appearance of the crystal habit in Fe1-x-Cox(x= 0-1) films. The films were vapor-deposited at an incidence angle of 65° on glass substrates heated at 673 K. Replica electron microscopy and the X-ray Schulz method showed that (i) the inclination angle of columnar grains depends on x, but the bundle is not formed in all the films, and (ii) in the bcc phase (x<0.85) the columnar grains exhibit the {100} and {110} habits not only on their tops but also on their sides. By analyzing directions of the column axis and the habit planes we concluded that the formation of the columnar grain structure is affected by the crystal habit.

The geometric alignment of crystallites was investigated using ellipsometry for evaporated cobalt films. The incidence angle was 45° and the gas pressure ranged from 0.008 to 2 Pa during argon gas inflow. The anisotropy of the reflection coefficient showed that above 0.6 Pa, crystallites preferentially align in the direction parallel to the incidence plane. The parallel alignment of crystallites is also found in sputtered films and is always accompanied by a c-axis preferred orientation. Replica electron microscopic observation and X-ray analysis revealed that the top of columnar grains constituting the parallel alignment is surrounded by the {101} habit planes, and the side of the columnar grains is truncated by the {0001} habit planes. Thus, we concluded that the parallel alignment is determined by the crystal habit.