Reference stress method for evaluation of failure assessment curve of cracked pipes in nuclear power plants

In order to obtain a precise failure assessment curve (FAC) in the R6 defect assessment procedure, it is necessary to evaluate the J-value of cracked components. The reference stress method can be used for estimating J-values. However, the accuracy of estimation depends on the limit load used for evaluating the reference stress. In this study, the applicability of several limit load solutions was investigated through comparison with the results of elastic-plastic finite element analyses (FEA). A pipe containing a circumferential surface crack was analyzed under pure bending load. Six materials used in nuclear power plants were assumed. It was shown that the reference stress method is valid for FAC evaluation. The maximum non-conservativeness caused by using the reference stress method is less than 20% compared to the results obtained by FEA.     

Superconducting MgB2 Thin Film Detector for Neutrons

The superconducting neutron detector using high-quality ¹⁰B-enriched MgB₂ thin films at higher operating temperatures has been proposed, where a resistance change induced by the nuclear reaction of neutron and ¹⁰B in MgB₂ is used to detect a neutron. Cold neutrons from a nuclear research reactor irradiated the MgB₂ detector, and the output voltage was clearly observed through a low-noise amplifier by using a digital oscilloscope. The out-of-equilibrium thermodynamics was investigated by means of the time-dependent Ginzburg-Landau equations by using the Earth Simulator.      

Crystal growth and structure of R2Ir2O7 (R = Pr, Eu) using molten KF

Single crystals of R₂Ir₂O₇ (R = Pr, Eu) have been synthesized using molten KF at 1373 K. The pyrochlore compounds crystallize in a cubic space group (No. 227, origin choice 2), with Z = 8. At room temperature, the lattice parameters are a = 10.3940(4) Å, V = 1122.92(7) Å³ and a = 10.274(3) Å, V = 1084.5(6) Å³ for Pr₂Ir₂O₇ and Eu₂Ir₂O₇, respectively. In this paper, we report the crystal growth of R₂Ir₂O₇ (R = Pr, Eu) and their structure determinations from single crystal X-ray diffraction experiments at temperatures of 110, 115, and 298 K.     

Atomic force microscopy based tunable local anodic oxidation of graphene

We have fabricated graphene/graphene oxide/graphene (G/GO/G) junctions by local anodic oxidation lithography using atomic force microscopy (AFM). The conductance of the G/GO/G junction decreased with the bias voltage applied to the AFM cantilever V(tip). For G/GO/G junctions fabricated with large and small |V(tip)|. GO was semi-insulating and semiconducting, respectively. AFM-based LAO lithography can be used to locally oxidize graphene with various oxidation levels and achieve tunability from semiconducting to semi-insulating GO.     

A Distortion Shaping Technique to Equalize Intermodulation Distortion Performance of Interpolating Arbitrary Waveform Generators in Automated Test Equipment

This paper demonstrates a phase switching algorithm for Interpolating Digital-to-Analog Converter (DAC) based Arbitrary Waveform Generator (AWG) that resides in Automated Test Equipment (ATE) to test semiconductor devices. This confirms a previous exercise that was made by experiment with different Intermodulation Distortion (IMD) suppression techniques and starting phase shifts to suppress IMD tones of the AWG with the interpolating DAC. We show that the poor performance of the AWG can be improved by using the phase switching algorithm over the installed base of a company’s tester platform. It is also shown that the IMD performance of AWGs across a company’s tester installed base can be equalized, and how it can be achieved using the phase switching technique. We describe how the IMD specifications of the instrument are much worse than those actually measured, and by using phase switching, better performance can be achieved than what would be possible under normal conditions. We present how this technique allows the use of a low-cost tester resource to test IMD products of such as communication application ADCs with a higher dynamic range than what was previously possible.     

Theoretical Consideration on Triplet Superconductivity in UPt3 and Sr2RuO4

Two representative superconductors, UPt₃ and Sr₂RuO₄, are comparatively studied on the basis of a general symmetry argument. The existing experimental data set for both systems strongly and commonly points to a triplet pairing. For the former, heavy fermion material, UPt₃, a non-unitary bipolar state is the most possible candidate, whereas for the latter system, Sr₂RuO₄, determination of a precise pairing symmetry class, either unitary or non-unitary, is debated.     

Characteristics of dispersion free single-mode fiber in the 1.5 µm wavelength region

Characteristics of dispersion free single-mode fibers in the wavelength regions 1.5 and 1.3 μm are compared experimentally and theoretically. We consider the influence of the refractive index profile on dispersion, the tolerance limits of structure parameters for minimum dispersion, attainable fiber bandwidth, and transmission loss including splicing and bending losses. For a fiber designed for minimum dispersion at 1.5 μm, the measured fiber loss was less than 1 dB/km and bandwidth was 250 GHz. km. nm. The achievable minimum loss estimation shows the advantage of dispersion free fibers at the 1.5 μm wavelength over dispersion free fibers at 1.3 μm.