Comment on "Conductance fluctuations in mesoscopic normal-metal/superconductor samples"

Recently, Hecker et al. [Phys. Rev. Lett. 79, 1547 (1997)] experimentally studied magnetoconductance fluctuations in a mesoscopic Au wire connected to a superconducting Nb contact. They claimed to have observed an enhancement of the rms magnitude of these conductance fluctuations in the superconducting state (rms(Gns)) relative to that in the normal state (rms(Gn)) by a factor of 2.8. In this comment, we argue that the measured rms(Gns) is NOT significantly enhanced compared to rms(Gn) when we correct for the presence of an incoherent series resistance from the contacts, which is different when Nb is in the superconducting or normal state.Comment: 1 pag

Two-point motional Stark effect diagnostic for Madison Symmetric Torus

A high-precision spectral motional Stark effect (MSE) diagnostic provides internal magnetic field measurements for Madison Symmetric Torus (MST) plasmas. Currently, MST uses two spatial views-on the magnetic axis and on the midminor (off-axis) radius, the latter added recently. A new analysis scheme has been developed to infer both the pitch angle and the magnitude of the magnetic field from MSE spectra. Systematic errors are reduced by using atomic data from atomic data and analysis structure in the fit. Reconstructed current density and safety factor profiles are more strongly and globally constrained with the addition of the off-axis radius measurement than with the on-axis one only

Reply to the Comment of den Hartog and van Wees on "Conductance Fluctuations in Mesoscopic Normal-Metal/Superconductor Samples"

In their comment cond-mat/9710285 [Phys. Rev. Lett. 80, 5024 (1998)] den Hartog and van Wees (HW) raise objections against our analysis of the experimental data presented in cond-mat/9708162 [Phys. Rev. Lett. 79, 1547 (1997)]. According to HW, we did not account for the quantum phase incoherence introduced by the Niobium compounds of the investigated Nb/Au hybrid samples. Here we show that and why this criticism is not justified. Some difficulties associated with a precise determination of the coherence lengths are discussed. It is discussed why these uncertainties do not have a qualitative impact on the results reported in our paper.Comment: Reply to the comment cond-mat/9710285 by den Hartog and van Wees; 1 page REVTE

Fe I Oscillator Strengths for the Gaia-ESO Survey

The Gaia-ESO Public Spectroscopic Survey (GES) is conducting a large-scale study of multi-element chemical abundances of some 100 000 stars in the Milky Way with the ultimate aim of quantifying the formation history and evolution of young, mature and ancient Galactic populations. However, in preparing for the analysis of GES spectra, it has been noted that atomic oscillator strengths of important Fe I lines required to correctly model stellar line intensities are missing from the atomic database. Here, we present new experimental oscillator strengths derived from branching fractions and level lifetimes, for 142 transitions of Fe I between 3526 {\AA} and 10864 {\AA}, of which at least 38 are urgently needed by GES. We also assess the impact of these new data on solar spectral synthesis and demonstrate that for 36 lines that appear unblended in the Sun, Fe abundance measurements yield a small line-by-line scatter (0.08 dex) with a mean abundance of 7.44 dex in good agreement with recent publications.Comment: Accepted for publication in Mon. Not. R. Astron. So

Vibration suppression and coupled interaction study in milling of thin wall casings in the presence of tuned mass dampers

Damping of machining vibrations in thin-wall structures is an important area of research due to the ever-increasing use of lightweight structures such as jet engine casings. Published literature has focussed on passive/active damping solutions for open geometry structure (e.g. cantilever thin wall), whereas more challenging situations such as closed geometry structures (e.g. thin wall ring-type casings) were not taken into consideration. In this study, a passive damping solution in the form of tuned viscoelastic dampers is studied to minimise the vibration of thin wall casings while focussing on the change in coupled interaction between tool and workpiece due to added tuned dampers. Finite element simulation was carried out to evaluate the effectiveness of tuned dampers in single impact excitation, and this was further validated experimentally through modal impact testing. A reduction in root mean square value, with tuned dampers, of about 2.5 and 4 times is noted at higher and lower depths of cut, respectively, indicating a moderate dependency on depth of cut. A change in coupled interaction of workpiece with tool’s torsional mode (in undamped state) to that of tool’s bending mode (with tuned dampers) was also noted. Variation in machined wall thickness of the order of 6 mm is noted due to the change in coupled interaction from torsional mode to bending mode of tool

Experimental determination of the quasi-particle decay length ξSm\xi_{\text{Sm}} in a superconducting quantum well

We have investigated experimentally the electronic transport properties of a two-dimensional electron gas (2DEG) present in an AlSb/InAs/AlSb quantum well, where part of the toplayer has been replaced by a superconducting Nb strip, with an energy gap $\Delta_0$. By measuring the lateral electronic transport underneath the superconductor, and comparing the experimental results with a model based on the Bogoliubov-de Gennes equation and the Landauer-B\"uttiker formalism, we obtain a decay length $\xi_{\text{Sm}} \approx 100~\text{nm}$ for electrons. This decay length corresponds to an interface transparency $T_{\text{SIN}}=0.7$ between the Nb and InAs. Using this value, we infer an energy gap in the excitation spectrum of the SQW of $\Delta_{\text{eff}} = 0.97 \Delta_0 = 0.83~\text{meV}$.Comment: Revtex, 3 PostScript figure

Radiolysis of NaCl at high and low temperatures: development of size distribution of bubbles and colloids

New experimental results are presented on low temperature irradiation (18 °C) of rock-salt samples which had been exposed to initial doses up to 320 GRad at 100 °C. Differential scanning calorimetry (DSC) shows that the latent heat of melting (LHM) of sodium colloids decreases during subsequent low-temperature irradiation, whereas the stored energy (SE) increases slowly, indicating that the process of radiolysis continues. The decrease of the LHM is due to dissolution of large colloids, because the intensities of the melting peaks decrease during the second stage irradiation at low temperature. The model is formulated to describe the nucleation kinetics and the evolution of the size distribution of chlorine precipitates and sodium colloids in NaCl under high dose irradiation. It is shown that the mechanism of dissolution of large Na colloids during low temperature irradiation can be related to melting of sodium colloids.

How Well Can we Diagnose Autism in Adults? Evaluating an Informant-based Interview: The Dutch Developmental, Dimensional and Diagnostic Interview – Adult Version (3Di-Adult)

The current study evaluated a brief, informant-based autism interview: the Developmental, Dimensional and Diagnostic Interview – Adult Version (3Di-Adult). Feasibility, reliability and validity of the Dutch 3Di-Adult was tested amongst autistic participants (n = 62) and a non-autistic comparison group (n = 30) in the Netherlands. The 3Di-Adult consists of two scales based on DSM-5 criteria: A scale ‘Social communication and social interaction’ and B scale ‘Restricted, repetitive patterns of behavior, interests or activities’. ROC curves were used to determine cut-off scores for the A and the B scale, using an ASD diagnosis made by an independent clinician as the criterion. Mean administration time was 42 min. Internal consistency of the A scale (α = 0.92) and the B scale (α = 0.85) were good. Inter-rater reliability (ICCs = 0.99) and inter-rater agreement (ICCs ≥ 0.90) were promising. The 3Di-Adult showed good sensitivity (80.6%) and specificity (93.3%). Positive and negative predictive value were 96.2% and 70.0% respectively. Comparisons with the Autism-Spectrum Quotient-Short to investigate the convergent validity showed moderate, significant correlations with the 3Di-Adult in the total sample. Males, as compared to females, displayed significantly more autistic features on the 3Di-Adult. No relationship was found of the 3Di-Adult with education level, intelligence and age of the participants or informants. The feasibility and psychometric properties of the Dutch 3Di-Adult are promising, indicating that it can be a time-efficient, valid and reliable tool to use in diagnosing autism in adults according to DSM-5 criteria