Abstract Objectives Employ conventional X-ray diffraction (XRD) to analyze three clinically important nickel–titanium orthodontic wire alloys over a range of temperatures between 25 and −110 °C, for ...comparison with previous results from temperature-modulated differential scanning calorimetry (TMDSC) studies. Methods The archwires selected were 35 °C Copper Ni–Ti (Ormco), Neo Sentalloy (GAC International), and Nitinol SE (3M Unitek). Neo Sentalloy, which exhibits superelastic behavior, is marketed as having shape memory in the oral environment, and Nitinol SE and 35 °C Copper Ni–Ti also exhibit superelastic behavior. All archwires had dimensions of 0.016 in. × 0.022 in. (0.41 mm × 0.56 mm). Straight segments cut with a water-cooled diamond saw were placed side-by-side to yield a 1 cm × 1 cm test sample of each wire product for XRD analysis (Rint-Ultima+ , Rigaku) over a 2 range from 30° to 130° and at successive temperatures of 25, −110, −60, −20, 0 and 25 °C. Results The phases revealed by XRD at the different analysis temperatures were in good agreement with those found in previous TMDSC studies of transformations in these alloys, in particular verifying the presence of R-phase at 25 °C. Precise comparisons are not possible because of the approximate nature of the transformation temperatures determined by TMDSC and the preferred crystallographic orientation present in the wires. New XRD peaks appear to result from low-temperature transformation in martensite, which a recent transmission electron microscopy (TEM) study has shown to arise from twinning. Significance While XRD is a useful technique to study phases in nickel–titanium orthodontic wires and their transformations as a function of temperature, optimum insight is obtained when XRD analyses are combined with complementary TMDSC and TEM study of the wires.
Primordial gravitational waves generated by inflation have produced an odd-parity pattern B-mode in the cosmic microwave background (CMB) polarization. LiteBIRD (Light satellite for the studies of ...B-mode polarization and Inflation from cosmic background Radiation Detection) aims at detecting this B-mode polarization precisely. It requires about 2000 detectors capable of detecting a frequency range from 50GHz to 250GHz with ultra low noise. Superconducting detectors are suitable for this requirement. We have fabricated and tested microwave kinetic inductance detectors (MKIDs) and developed a new readout system.
We have designed antenna-coupled MKIDs. Quasi-particles are created by incident radiation and are detected as a change of the surface impedance of a superconductor strip. This change of the surface impedance is translated into the change of the resonant frequency of a microwave signal transmitted through the resonator.
We also have developed a new readout system for MKIDs. The newly developed readout system is not only able to read out the amplitude and the phase data with the homodyne detection for multi-channels, but also provides a unique feature of tracking the resonant frequency of the target resonator. This mechanism enables us to detect signals with a large dynamic range. We report on the recent R&D status of the developing MKIDs and on the read-out system for LiteBIRD.
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