Miracle-dz/UniFAR-FTUs huggingface dataset:
Material transport by erosion and redeposition on surface probes in the scrape-off layer of JET

The material transport by erosion and redeposition at the plasma facing wall areas in high temperature plasma experiments has been studied using limiter-like carbon probes with well defined surface deposits and depth markers. The probes have been exposed in the scrape-off layer (SOL) of the Joint European Torus (JET) during single discharges. For the evaluation of these experiments a computer program, ERO, has been developed. The calculated erosion-deposition rates for carbon as a function of the distance to the last closed flux surface (LCFS) agree well with the experimental results. For a single 4He JET discharge, erosion yields of 530 A for the silicon deposit and 80 A for vanadium have been measured near the LCFS. A large amount of redeposited silicon (about 17% of the sputtered atoms) has been found on the probe surface in co-deposition with carbon on an area not favoured by the proposed model. This observation can be explained by an additional force on the impurity ions (e.g. the existence of a local electric field), which may cause the deposition
Chemical profiling of single nanotubes: Intramolecular p–n–p junctions and on-tube single-electron transistors

Electrical transport properties of intramolecular p–n–p junctions formed on individual semiconducting carbon nanotubes are reported. Chemical dopant “profiling” along the length of a nanotube divides the nanotube into two p-doped sections and a central n-doped section. The double p–n junctions formed on the nanotube dictate the electrical characteristics of the system. Well-defined and highly reproducible single-electron transistors with much smaller size than the geometrical length of the nanotube are obtained.
The axis ratio distribution of faint galaxies: Evidence for a populatin of dwarfgalaxies at I approximately 20.5

The axis ratio distribution of faint galaxies observed by the Hubble Space Telescope (HST) as part of the Medium Deep Survey (MDS) key project suggests that a very large fraction of the total population at magnitudes I greater than or equal to 20 mag consists of a class of galaxies with luminosity profile, axis ratio distribution, angular size, and color that resemble local dwarfs. We find that galaxies with exponential light profiles and small angular sizes (half-light radius less than 0.6 sec) have an axis ratio distribution that is incompatible with their being intrinsically flattened objects and is instead consistent with local elliptical galaxies. We call these objects 'Small Exponential Ellipticals. ' They are most likely dwarf galaxies, and they are numerous enough that, together with irregular galaxies, they can account for most if not all of the excess in the number counts at I approximately 20-21 mag with respect to the standard no-evolution models. This may suggest that the excess number counts are best explained by dwarf-rich models with strong luminosity evolution of the dwarf galaxies. Our data also supports a very mild luminosity evolution of the giant galaxy populations, which contributes little to the excess number counts.
Enhanced performance by incorporation of zinc oxide nanowire array for organic-inorganic hybrid solar cells

We study the solar power conversion efficiency in hybrid solar cells based on zinc oxide (ZnO)/antimony trisulfide (Sb2S3)/poly-3(hexylthiophene) heterojunctions. The incorporation of ZnO nanowire arrays (NAs) structure results in power conversion efficiency of 2.9%, or 20% higher than the control device. Absorption spectra and numerical simulation analysis provide strong evidence revealing that the enhanced performance is mainly induced by (1) enhanced optical absorption from light-trapping effect of NAs and (2) reduced bulk recombination rate in Sb2S3 from shortened electron injection pathway into ZnO. Significantly, numerical simulations show that the expected interface recombination increase from larger interfacial area effects is negligible.
Spatial and temporal transformation of femtosecond laser pulses by lenses and lens systems

A Fourier-optical analysis of the transformation of ultrashort light pulses by lenses is given. Inserting the material dispersion up to second order, we find a coupling between the temporal, spectral, and spatial properties of the light pulse. In general, this coupling leads to a drastic increase in pulse duration and width of the spatial intensity distribution in the focal plane of the lens, which can be avoided with the use of achromatic lens doublets. The results are discussed for Gaussian-shaped input pulses.
Diversity in diversification: an analysis of shopping trips in six-week travel diary data

Diversification in shopping, a long-pursued subject in consumer behavior analysis, is approached from a broad perspective of the diversity in daily travel patterns, which may or may not involve shopping trips, as well as the diversity in shopping locations and frequency. The focus of this analysis is on the heterogeneity across individuals in the ways in which they each diversify their respective shopping behavior. This study explores differences across individuals in the variations of their shopping travel patterns across days. Treating the day-of-the-week evolution of shopping travel patterns as a stochastic process, characteristics of diversification are quantified for respective individuals. Finally, heterogeneity across individuals is identified using an array of statistical methods. The analysis, based on results of a six-week travel diary survey in Germany with geo-coded activity locations, reveals the effects of individual, household, and urban attributes on diversification in shopping behavior, including that full-time workers with medium incomes (4000–4999 Deutsche Mark per month) tend to have more variations in their shopping engagement.
Metastability of Northern Hemisphere Teleconnection Modes

AbstractThis study applies a finite-element, bounded-variation, vector autoregressive method to assess midtropospheric flow regimes characterized by regime switches between metastable states. The flow is assessed in reanalysis data from three different reanalysis sets assimilating surface data only; surface and upper-air data; and ocean, surface, and upper-air data. Results are generally consistent across the reanalyses and confirm the utility of surface-only reanalyses for capturing midtropospheric variability. The method is applied to a set of regional domains in the Northern Hemisphere and for the full-hemispheric domain. Composites of the metastable states for each region yield structures that are consistent with the well-documented teleconnection modes: the North Atlantic Oscillation in the Atlantic Ocean, the Pacific–North America pattern (PNA) in the Pacific Ocean, and Scandinavian blocking over Eurasia. The PNA mode includes a clear waveguide structure in midlatitudes. The Northern Hemisphere doma.
An Iterative Domain Decomposition Method for Solving Wave Propagation Problems

Abstract Solving electromagnetic wave propagation problems with the finite-element method results in a large number of unknowns due to the necessity of modeling an extensive portion of the surroundings of the conducting structures. These equation systems are often ill-conditioned because of the great material differences as well as changes in size between neighboring elements. In addition, the resulting matrices are indefinite. Common iterative methods exhibit poor convergence due to these conditions. Direct solution techniques result in high memory requirements. The aim of this article is to present an approach with smaller memory demand than the direct methods and better convergence properties than common iterative techniques. An iterative method based on domain decomposition is presented and compared to various conventional iterative and direct solution techniques.
Approximation of sigmoid function and the derivative for hardware implementation of artificial neurons

A piecewise linear recursive approximation scheme is applied to the computation of the sigmoid function and its derivative in artificial neurons with learning capability. The scheme provides high approximation accuracy with very low memory requirements. The recursive nature of this method allows for the control of the rate accuracy/computation-delay just by modifying one parameter with no impact on the occupied area. The error analysis shows an accuracy comparable to or better than other reported piecewise linear approximation schemes. No multiplier is needed for a digital implementation of the sigmoid generator and only one memory word is required to store the parameter that optimises the approximation.
Monolithic hybrid optics for broadband focusing and beam shaping

Almost any application that involves more than one wavelength going through an optical system has same need for color correction. Thus, the common approach is to add more surfaces and balance the optical glass in order to achieve this goal. For some applications, especially when ultrashort laser pulses (pulse durations way below 100fs) are involved, it is quite important to reduce the amount of higher order dispersion in an optical system because it is basically impossible to compensate for them afterwards. Therefore, we pursue a different approach. We present two different specially designed monolithic hybrid optics comprising refraction and diffraction effects for tight spatial and temporal focusing of ultrashort laser pulses. Both aims can be put into practice by having a high numerical aperture (NA=0.5 and 0.7) and low internal dispersion at the same time. The focusing properties of the first example are very promising, due to a design, which provides diffraction limited focusing for 80nm bandwidth at 780nm center wavelength. Thus, pulses with durations as short as 25fs can be focused without pulse front distortion. The outstanding performance of such optics is shown. The approach for the second focusing optics goes even further beyond common designs. It not only combines refraction with diffraction, but also involves total internal reflection for beam shaping and therefore improving focusing quality even further while reducing the spot size. This optics is especially interesting for nonlinear material processing.
A Global Existence Theorem for Large Eddy Simulation Turbulence Model

In this work we show the existence and uniqueness in Sobolev spaces of the solution of Large Eddy Simulation turbulence model for any time provided that initial data and external forces are regular and small enough. We also show that if external forces are time-periodic or time-independent, then the solution is time-periodic or time-independent.
Mitochondrial phosphoenolpyruvate carboxylase contributes to carbon ﬁxation in the diatom Phaeodactylum tricornutum at low inorganic carbon concentrations

(PEPC) is present in two isoforms, PEPC1 in the plastids and PEPC2 in the mitochondria. We used real-time quantitative polymerase chain reaction, Western blots, and enzymatic assays to examine PEPC expression and PEPC activity, under low and high concentrations of dissolved inorganic carbon (DIC). (cid:1) We generated and analyzed individual knockout cell lines of PEPC1 and PEPC2, as well as a PEPC1/2 double-knockout strain. While we could not detect an altered phenotype in the PEPC1 knockout strains at ambient, low or high DIC concentrations, PEPC2 and the double-knockout strains grown under ambient air or lower DIC availability conditions showed reduced growth and photosynthetic afﬁnity for DIC while behaving similarly to wild-type (WT) cells at high DIC concentrations. These mutants furthermore exhibited signiﬁcantly lower 13 C/ 12 C ratios compared to the WT. (cid:1) Our data imply that in P. tricornutum at least parts of the CCM rely on biochemical bicarbonate ﬁxation catalyzed by the mitochondrial PEPC2.
Magnetic excitations from the linear Heisenberg antiferromagnetic spin trimer system A 3 Cu 3 ( P O 4 ) 4 ( A = Ca , Sr, and Pb)

Inelastic neutron-scattering experiments were performed on ${A}_{3}{\mathrm{Cu}}_{3}{(\mathrm{P}{\mathrm{O}}_{4})}_{4}$ ($A=\mathrm{Ca}$, Sr, and Pb), which consists of one-dimensional array of linear copper spin trimers. It was found that the magnetic excitations are well described by the linear Heisenberg antiferromagnetic spin trimer model, in which the main interaction is the nearest-neighbor intratrimer interaction and the weak next-nearest-neighbor intratrimer and intertrimer interactions are expected. The intratrimer coupling constants are determined to be 9.45(3), 10.04(3), and 9.13(2) meV for ${A}_{3}{\mathrm{Cu}}_{3}{(\mathrm{P}{\mathrm{O}}_{4})}_{4}$ with $A=\mathrm{Ca}$, Sr, and Pb, respectively. The other interactions were found to be very small.
Mesoscale Atmospheric Circulations over the Southwestern Ross Sea Sector, Antarctica

In this study the mesoscale atmospheric circulation over the southwestern Ross Sea sector during winter is examined. The hydrostatic meso-gamma-scale atmospheric model MAR (Modele Atmospherique Regional) is used. Polar night is assumed, and an idealized large-scale situation is prescribed, with zero geostrophic forcing. The impact of a partial sea-ice cover on the atmospheric circulation is assessed by prescribing lead fractions in the range of the observed values (i.e., between 0% and 30%). Simulations show that the propagation of katabatic airstreams over Terra Nova Bay is facilitated by the presence of leads because the identity of cold, dense, katabatic air is better marked in warmer environmental maritime conditions. Boundary layer fronts and mesocyclone activity are associated with the katabatic airstreams. They are enhanced by the presence of leads. In particular, when the lead fraction is prescribed to be between 20% and 30%, the model simulates mesocyclone intensities comparable to those observed. Taking into account that such a lead fraction is situated in the upper range of the observed values in the central Ross Sea during winter, these results suggest that winter Ross Sea mesocyclones could nor always result from a pure mesoscale forcing. In contrast to the summer situation, no snow precipitation occurs for the simulated winter case, probably because of the too-low absolute humidity content of the air. Such model behavior is in agreement with the observations, which reveal a summer precipitation maximum at McMurdo Station on Ross Island. It is also found that the position of the simulated mesocyclone over Terra Nova Bay is nor sensitive to the lead fraction. Furthermore, this meteorological situation favors the advection of relatively mild and moist maritime air over a long distance in the ice-sheet interior. This process, which is referred to as a moist-air intrusion, could affect the Antarctic ice-sheet mass balance.
The oscillation method for crystals with very large unit cells

The processing of data collected by oscillation photography from crystals with very large unit cells (average cell constant ∼ 250 A) requires important modifications of standard methods. In particular, it is often necessary to correct partially recorded intensities to their fully recorded equivalents. A procedure is described for accurate determination of relevant parameters (crystal setting, cell constants). It relies on the redundancy present in most data-collection strategies, which yields fully recorded, symmetry-related counterparts of a number of partially recorded reflections. A detailed description of one example (tomato bushy stunt virus) is presented, with complete intensity statistics.
Scattering by a finite periodic potential

The problem of scattering in one dimension by a potential which consists of N identical cells is solved in a transparent manner. The N‐cell transmission and reflection amplitudes are expressed in terms of the single‐cell amplitudes and the Bloch phase. As examples the results are applied to a row of delta‐function potentials, and to a row of square wells, and it is shown that these expressions provide an immediate understanding of the results of detailed calculations.
A NOTE ON THE CORRECTED SCORE FUNCTION ADJUSTING FOR MISCLASSIFICATION

This paper deals with a regression model with covariates subject to misclassification. Simply ignoring the misclassification generally yields bias in parameter estimation. A corrected score function (Nakamura, 1990) is developed to obtain asymptotically unbiased estimates adjusting for the misclassification. It is proved that a corrected score function always exists for a misclassification model whose likelihood consists of independent contributions. This existence theorem for misclassification model is conspicuous since corrected score functions do not always exist for measurement error models with continuous covariates. For instance, a corrected score function does not exist for a logistic model with continuous covariates subject to normal random error(Stefanski, 1989). For illustration, the correction method is applied to generalized linear models and a simulation study based on the logistic regression model is performed. The misclassification are assumed to be nondifferential, which is normally assumed with prospective studies.
Damage study for the design of the European XFEL beamline optics

The European X-Ray Free Electron Laser will deliver high intensity ultrashort pulses of x-rays. The results of the x-ray interaction with matter in such a regime are not yet fully understood and the energy threshold for surface modifications remains unknown. The behavior of optical components under irradiation is a major issue for the European XFEL project. In fact some experiments rely on the coherence and high quality wave front of the beam and any degradation, even on the nanometer scale, of the x-ray optical components will affect the performance of these experiments. Hence investigation of radiation effects on materials is needed. We will describe the on-going program at the European XFEL which aims at developing new approaches for beamline design specific to FEL light source. Different tools are used in order to simulate the beam propagation and interaction with optical elements.
Boltzmann Approach to Lattice Gas Simulations

An alternative simulation procedure is proposed for lattice hydrodynamics, based on the lattice Boltzmann equation instead of on the microdynamical evolution. The averaging step, used by the latter method to derive macroscopic quantities, is suppressed, as well as the associated fluctuations. The collision operator is expressed in terms of its linearized part, and condensed into a few parameters, which can be selected, independently of a particular collision rule, to decrease viscosity as much as desired.
Rayleigh-Taylor Instabilities and Mixing in the Helium Star Models for Type Ib/Ic Supernovae

Motivated by the necessity of large-scale mixing in modeling the light curves of Type Ib/Ic supernovae (SN Ib/Ic), the Rayleigh-Taylor (R-T) instabilities in exploding helium stars of masses M(alpha) = 3.3, 4, and 6 solar masses are calculated for the first time with a two-dimensional hydrodynamical code. Mixing of the ejected material induced by the instabilities is found to be more extensive for smaller mass stars. For M(alpha) less than about 4 solar masses, Ni-56 is mixed to the outermost helium envelope. For M(alpha) greater than about 6 solar masses, on the contrary, the growth of the R-T instability is too weak to convey Ni-56 into the outer layers. The extensive mixing in smaller mass stars is consistent with the early light curve models for SN 1983N (Type Ib) and SN 1987M (Type Ic) whose declines are as fast as and even faster than Type Ia supernovae. On the other hand, no significant mixing for larger M-alpha may be consistent with the slow decline of SN Ib 1984L. Thus the observed variation of the SN Ib/Ic light curves can naturally be accounted for by the variation of mixing as a function of the helium star mass. 29 refs.
Concept for laser guide star dynamic refocusing using rotating phase plates

Laser guide star wavefront sensors (WFS) using pulsed lasers can benefit from dynamic refocusing techniques which synchronously adjust the focus of the wavefront as the light returns from the scattering layer so as to maintain a constant axial image location. Existing techniques involve pulsating discrete mirrors and high-speed segmented MEMS in the WFS path. A different approach is presented here, which uses a pair of rotating phase plates with cylindrical or Alvarezlens- style tracks near the WFS pupil. Rotational speeds and disk sizes similar to that used for compact disc operation are proposed. The plates can be manufactured by numerical machining of transparent plastic materials or as diffractive components.
Predictions of multivariate autoregressive-moving average models

SUMMARY A simple formula for multiperiod predictions of multivariate autoregressive-moving average models is derived.The formula is explicitly given as a function of suitably defined parameter matrices and an observation vector, and includes simpler models as its special cases. The asymptotic prediction mean squared error is also derived for predictions with estimated parameters.
Apodized aperture imaging optics for Compton-scattered x-ray and gamma-ray imaging systems

To improve the resolution and field of view of high-energy Compton-scattered x-ray and gamma-ray imaging systems, we have developed and tested apodized imaging optics based on apertures with depth-dependent cross sections fabricated in an x-ray-absorbing material. Through ray-tracing modeling, we determined the optimum aperture shapes (apodizations) that maximize the field of view and/or resolution of the system. Such apodized apertures can be used either in single-aperture optics, or in coded-aperture arrays. Potential applications of this technology include nondestructive evaluation (NDE) of materials and structures, in particular Compton imaging tomography (CIT), x-ray and gamma-ray astronomy, and medical imaging.
Practical considerations of joint friction and backlash in large ground-based telescope secondary optic positioning systems

Secondary mirrors and lenses in several planned ground-based telescopes have masses on the order of 5000 kg and require a positioning system that is repeatable to one-tenth the pixel size of the optical sensors, nominally 10 micrometers or less. Hexapods, or Stewart Platforms, are frequently integrated into the support structure as six degree of freedom parallel positioning and alignment systems. These systems are limited in resolution by friction in the 36 kinematic degrees of freedom (DOF) necessary for properly constrained motion of the platform. The 30 passive DOF, typically implemented with one 3-DOF and one 2-DOF joint on each hexapod leg, introduce unwanted friction and/or backlash into the positioning system. Backlash is generally unacceptable and elimination requires significant preloading of the joints, which in turn increases joint friction. This paper will: review various joint types including rolling element, plain bearing (sliding), and flexure; examine the backlash and friction tradeoffs involved in selecting joint type including unwanted deflections due to joint moments, static position resolution limitations, dynamic positioning settling time effects, self-locking mechanisms, and power dissipation; compare with experimental data and previously published results; present methods for modeling both static and dynamic effects of friction; and suggest recommendations for general positioning system design. Considerations for both equatorial and altitude-azimuth telescopes will be discussed, along with variation of effects due to telescope positioning. Analyses will be reinforced with friction and backlash measurements made on several physical joints.