Miracle-dz/UniFAR-FTUs huggingface dataset:
A counterexample to the fourteenth problem of Hilbert in dimension three

Let K be a field, K[X] = K[X1, . ,Xm] the polynomial ring in m variables over K, and K(X) its field of fractions. Then, the fourteenth problem of Hilbert asks whether the K-subalgebra L∩K[X] of K[X] is finitely generated whenever L is a subfield of K(X) containing K. Zariski [23] showed that L ∩ K[X] is finitely generated if the transcendence degree of L over K is at most two. Consequently, the problem has an affirmative answer if m ≤ 2. On the other hand, a counterexample to the problem was first found by Nagata [17] in 1958 form ≥ 32 (see [8] for the progress on this problem). Recently the author [12] gave a counterexample for m = 4, whereby the problem remained open only for m = 3. In fact, if L∩K[X] is not finitely generated, then L ∩K[X][Xm+1, . ,Xm+r ] is also not finitely generated for each r ≥ 0. In this paper we give the first counterexample to the problem for m = 3. Thus, the fourteenth problem of Hilbert is settled for all m at last. Let γ and δi,j be positive integers for i, j = 1, 2, and let 1 = X2,1 1 X−δ2,2 2 −X−δ1,1 1 X1,2 2 , 2 = X 3 −X−δ1,1 1 X1,2 2 , (1.1) 3 = 2Xδ2,1−δ1,1 1 Xδ1,2−δ2,2 2 −X−2δ1,1 1 X1,2 2 .
Activation of the 3.47 μm Band by H Atom Irradiation of Carbon Grains Covered with a Water Ice Layer at 12 K

We present the first results of laboratory research on the processing of nano-sized carbon particles under simulated dense-medium conditions. The experiments aim to study the variations of the degree of hydrogenation of carbon particles covered with a water ice layer in response to H atom exposure. The effects of H atom processing have been studied by means of IR spectroscopy. The results show that the formation of C-H bonds in the aliphatic CH2 and CH3 functional groups does not take place. The activation of a band at 3.47 μm is observed. It is assigned to the C-H stretching vibration of tertiary sp3 carbon atoms. The band profile is compatible with that present in the spectrum of sources embedded in dense clouds. We propose that the carbon grain population, which is responsible for the interstellar aliphatic 3.4 μm band in diffuse regions, absorbs at 3.47 μm in dense clouds.
The Science of Singing Voice

Althought there are numerous books dealing with the science and acoustics of speech, there are relatively few that deal with the singing voice as distinct from the speaking voice. Now, Johan Sundberg's "The Science of the Singing Voice" illustrated with over a hundred instructive and significant diagrams and drawings thoroughly describes the structure and functions of the vocal organs in singing, from the aerodynamics of respiration through the dynamics of articulation. "
Power lateral pnp transistor operating with high current density in irradiated voltage regulator

The operation of power lateral pnp transistors in gamma radiation field was examined by detection of the minimum dropout voltage on heavily loaded low-dropout voltage regulators LM2940CT5, clearly demonstrating their low radiation hardness, with unacceptably low values of output voltage and collector-emitter voltage volatility. In conjunction with previous results on base current and forward emitter current gain of serial transistors, it was possible to determine the positive influence of high load current on a slight improvement of voltage regulator LM2940CT5 radiation hardness. The high-current flow through the wide emitter aluminum contact of the serial transistor above the isolation oxide caused intensive annealing of the positive oxide-trapped charge, leading to decrease of the lateral pnp transistor's current gain, but also a more intensive recovery of the small-signal npn transistors in the control circuit. The high current density in the base area of the lateral pnp transistor immediately below the isolation oxide decreased the concentration of negative interface traps. Consequently, the positive influence of the reduced concentration of the oxide-trapped charge on the negative feedback reaction circuit, together with the favourable effect of reduced interface traps concentration, exceeded negative influence of the annealed oxide-trapped charge on the serial pnp transistor's forward emitter current gain.
On-the-job detection and correction of systematic cyclic distance measurement errors of terrestrial laser scanners

Abstract Application of terrestrial laser scanning for engineering and documentation projects requiring high accuracy is often prohibitive due to the error budget of terrestrial laser scanners (TLS) which is worse than that of alternative instruments such as total stations. However, by separating the errors of TLS into random and systematic components, the influence of both can be reduced significantly. Approaches for reducing the influence of random noise rely on averaging. One method is introduced briefly as it is relevant for the task of the proposed systematic error removal. We discuss the correction of cyclic distance measurement errors of TLS in detail. For the investigated scanner, these cyclic errors are the most dominant systematic errors. The proposed approach is based on an on-the-job determination of a distance correction function which allows reducing the magnitude of the occurring distance errors by a factor of ten, reducing the systematic errors to less than 0.5 mm. The massive amount of data acquired by TLS is exploited using robust statistical methods. The algorithm developed relies on small, flat surfaces found automatically in the scene. Hence, the method can be applied on engineering project data without requiring additional laboratory experiments. Therefore, it is not essential that the errors are constant over time. By the introduction of on-the-job correction procedures as the one proposed, the systematic errors of TLS can be decreased significantly. This makes them more suitable to be used as an alternative to single point measurement devices.
Trust region method for DOT image reconstruction

In this study, we measured the optical properties of optical tissue phantoms and human tissues by measuring the photon density distribution on the boundary of the phantoms and tissues and by using the Frequency-Domain DOT (Diffuse optical tomography) system. A trust region nonlinear optimization method is used for the image reconstruction in DOT. This method is a more elaborated Newton method which takes advantage of the classical Newton method and the gradient descent method. The validity of this method is verified by reconstructing the optical properties from phantom experiment and simulated data using the Frequency-Domain DOT system.
Model for the current–voltage characteristics of ultrathin gate oxides after soft breakdown

The current–voltage characteristics of metal-oxide-semiconductor capacitors with a 4.2 nm SiO2 gate oxide are investigated. After the occurrence of soft breakdown, which is observed during constant current stress of the devices, the gate current is shown to behave like a power law of the applied gate voltage. We propose that this power law behavior is due to the formation of a percolation path between the electrons traps generated in the SiO2 layer during current stress of the capacitor. We describe a simple model which accounts for the current–voltage characteristics between two neighbor trapping sites, as well as a distribution of percolation thresholds in these (finite size) ultrathin SiO2 layers. The prediction of the model is in fair agreement with the experimental results in a large voltage range, and leads to a better description of the data than previously reported models. Furthermore, it is shown that this percolation model can also explain the temperature dependence of the gate current after the.
Flow around a Circular Cylinder: Aspects of Fluctuating Lift

The paper is concerned with some aspects of the fluctuating lift acting on a stationary circular cylinder in cross flow, in particular effects of Reynolds number in the nominal case of a large-aspect-ratio cylinder at small to vanishing blockage and free-stream turbulence, respectively. The Reynolds number range covered is from about Re=47–2·2×105, i.e., from the onset of vortex shedding up to the point where a subsequent increase in Re gives a rapid fall in the mean drag coefficient, the all-familiar drag crisis. A review of 2-D numerical simulations suggests that the r.m.s. lift coefficient (CL′) within the laminar shedding regime can be approximated ase/30+e2/90, wheree =(Re−47)/47. For all Reynolds numbers above the inception of three-dimensional flow instabilities, i.e., for Re>(160–190), the near-wake flow is supposed to be partially correlated along the span. The lift fluctuations on a finite (spanwise) length of the cylinder are then not only dependent on the sectional lift variations but also on the spanwise correlation of the lift-related flow. At around Re=230, which is the approximate onset Re for mode B instability, the one-sided spanwise correlation length (Λ) is about twice the wavelength of the most unstable mode A instability,Λ /d≈7. Up to Re=260–300 the spanwise correlation increases dramatically, the indicated peak value being Λ/d≈30. From 3-D numerical simulations, the correspondingCL′ is approximately 0·5, which coincidentally is about the same value as found experimentally just before the rapid fall when entering the critical regime. Dramatic variations of both sectionalCL′ and Λ/d occur within the range Re≃0·3×103–2·2×105. For instance, at around Re=1·6×103a local minimum of about CL′=0·045 is indicated, at Re≃16×103the corresponding CL′-value is ten times higher. At Re=5·1×103there is a peak in spanwise correlation, Λ/d≈15.
Methodology of splicing large air filling factor suspended core photonic crystal fibres

We report the methodology of effective low-loss fusion splicing a photonic crystal fibre (PCF) to itself as well as to a standard single mode fibre (SMF). Distinctly from other papers in this area, we report on the results for splicing suspended core (SC) PCF having tiny core and non-Gaussian shape of guided beam. We show that studied splices exhibit transmission losses strongly dispersive and non-reciprocal in view of light propagation direction. Achieved splicing losses, defined as larger decrease in transmitted optical power comparing both propagation directions, are equal to 2.71 ±0.25 dB, 1.55 ±0.25 dB at 1550 nm for fibre SC PCF spliced to itself and to SMF, respectively.
Effective slip on textured superhydrophobic surfaces

We study fluid flow in the vicinity of textured and superhydrophobically coated surfaces with characteristic texture sizes on the order of 10μm. Both for droplets moving down an inclined surface and for an external flow near the surface (hydrofoil), there is evidence of appreciable drag reduction in the presence of surface texture combined with superhydrophobic coating. On textured inclined surfaces, the drops roll faster than on a coated untextured surface at the same angle. The highest drop velocities are achieved on surfaces with irregular textures with characteristic feature size ∼8μm. Application of the same texture and coating to the surface of a hydrofoil in a water tunnel results in drag reduction on the order of 10% or higher. This behavior is explained by the reduction of the contact area between the surface and the fluid, which can be interpreted in terms of changing the macroscopic boundary condition to allow nonzero slip velocity.
Time-resolved photoluminescence studies of the energy transfer from excitons confined in Si nanocrystals to oxygen molecules

The formation of singlet oxygen due to the energy transfer from excitons confined in silicon nanocrystals to oxygen molecules is studied using time-resolved photoluminescence spectroscopy. The process of the excitation of oxygen molecules from the ground triplet state to the second excited singlet state is studied at low temperatures, where oxygen molecules are physisorbed on the surface of silicon nanocrystals and at room temperature in gaseous oxygen ambient and in oxygen-saturated water. The low temperature measurements reveal that the energy transfer time is the shortest for the resonant energy transfer. The involvement of one energy-conserving transversal optical phonon results in about 40% increase of the energy transfer time. The excitation rate of oxygen dimers is found to be similar to that measured for oxygen molecules. At room temperature, the time of the energy transfer to oxygen molecules is about 17 mu s. The photosensitizing efficiency of silicon nanocrystals at room temperature is found to be as high as 80% for gaseous oxygen ambient and for oxygen-saturated water.
Using DARC in a multi-object AO bench and in a dome seeing instrument

The Durham adaptive Optics Real Time Controller (DARC)1 is a real-time system for astronomical adaptive optics systems originally developed at Durham University and in use for the CANARY instrument. One of its main strengths is to be a generic and high performance real-time controller running on an off-the-shelf Linux computer. We are using DARC for two different implementations: BEAGLE,2 a Multi-Object AO (MOAO) bench system to experiment with novel tomographic reconstructors and LOTUCE2,3 an in-dome turbulence instrument. We present the software architecture for each application, current benchmarks and lessons learned for current and future DARC developers.
Experimental evaluation of an airborne depth-sounding lidar

An experimental evaluation of an airborne depth sounding lidar called FLASH (FOA Laser Airborne Sounder for Hydrography) is presented. The lidar is based on a scanning frequency doubled Nd-YAG laser and is borne by a helicopter. An example of measured waveforms is compared with those obtained by analytical and Monte Carlo modeling.
Angular Momentum Transport in Magnetized Stellar Radiative Zones. IV. Ferraro’s Theorem and the Solar Tachocline

We consider the circumstances under which the latitudinal differential rotation of the solar convective envelope can (or cannot) be imprinted on the underlying radiative core through the agency of a hypothetical weak, large-scale poloidal magnetic field threading the solar radiative interior. We do so by constructing steady, two-dimensional axisymmetric solutions to the coupled momentum and induction equations under the assumption of a purely zonal flow and time-independent poloidal magnetic field. Our results show that the structure of the interior solutions is entirely determined by the boundary conditions imposed at the core-envelope interface. Specifically, in the high Reynolds number regime a poloidal field having a nonzero component normal to the core-envelope interface can lead to the transmission of significant differential rotation into the radiative interior. In contrast, for a poloidal field that is contained entirely within the radiative core, any differential rotation is confined to a thin magnetoviscous boundary layer located immediately beneath the interface, as well as along the rotation/magnetic axis. We argue that a magnetically decoupled configuration is more likely to be realized in the solar interior. Consequently, the helioseismically inferred lack of differential rotation in the radiative core does not necessarily preclude the existence of a weak, large-scale poloidal field therein. We suggest that such a field may well be dynamically significant in determining the structure of the solar tachocline.
Estimation efficiency with omitted covariates in generalized linear models

Abstract Although omitting covariates associated with the response in generalized linear models can yield seriously biased estimates of the effects of the included covariates, in certain settings there is no bias. This article considers the effect of omitted covariates on the efficiency of the estimated effects of the included covariates in these cases. I consider the case where the omitted covariate is independent of the included covariates, as in studies with randomized treatment assignment, as well as the case where the omitted covariate is correlated with the included but not a confounder. I present expressions to show that omitting covariates associated with the response and independent of the included covariate can result in serious efficiency losses for estimates of the effects of the included covariates. I also present expressions to show that omitting nonconfounding covariates can lead to efficiency gains. These expressions also quantify the magnitude of estimation efficiency with omitted covaria.
Measurements of X-Ray Source Positions by the Scanning Modulation Collimator on HEAO-1.

This paper reports preliminary results on the positions of X-ray sources obtained with the modulation collimator on the first NASA High Energy Astronomy Observatory, HEAO 1. Calibration on Sco X-1 establishes the experiment capabilities to be within 7 sec as limited by aspect errors. For the reported X-ray sources certain ambiguities in their positions are resolved and the previous optical identifications of four sources are confirmed, two of which are X-ray bursters and one of which is the black hole candidate Cir X-1. An accurate position for a new transient source is also presented.
lonization in low-energy atomic collisions

The ionization processes which occur in the collisions of atoms at thermal energies are reviewed. The various experimental methods used to study ionization are discussed; these methods include spectroscopy of decaying plasmas, particle-beam methods for studying particle collisions, Penning electron spectroscopy, massspectrometric detection of reaction products, and methods for selectively exciting the atoms involved in collisions. Information on the cross sections and rate constants of Penning processes, associative ionization, and ionization involving a resonantly excited atom is reported. Results are reported on the spectra of the electrons freed in these ionization processes and on the probabilities for various particular reactions. Theoretical models for ionization in low-energy atomic collisions are discussed.
Hydrodynamic lift of a moving nano-rod at a wall

The hydrodynamic lift of a nano-rod that is pulled parallel to a wall is studied using hydrodynamic simulations and scaling arguments at finite temperature in the zero-Reynolds number limit. The no-slip wall gives rise to a hydrodynamic torque and partial rod orientation, which in turn induces a long-ranged hydrodynamic repulsion away from the wall. At high temperatures, the lift force depends quadratically on the pulling force and decays inversely with the square of the separation from the surface.
Robust multi-object sensor fusion with unknown correlations

Distribution and decentralisation of fusion operations are key to network centric operations (NCOs) and distributed data fusion algorithms (DDF) have been developed to support them. These algorithms fuse data collected locally with state estimates propagated from other nodes. If the full advantages of NCOs are to be realised, these algorithms should exploit local information only: no single node, for example, should be an oracle which must maintain the entire state of the network. Uhlmann argued that many of these could be overcome if suboptimal solutions were used and proposed a principled suboptimal algorithm known as Covariance Intersection (CI). CI has proved to be a very powerful and general method for fusing data in arbitrary networks and has been used in a range of distributed and other applications where full correlation structures cannot be maintained. However, CI only utilizes the mean and covariance of the estimates and cannot exploit any additional distribution information such as the number of modes. The generalisation of CI to general probability distributions was first proposed by Mahler and independently derived by Hurley. We investigate the generalisation Covariance Intersection for multi-object posteriors by considering specific forms of multi-object posterior and their first-order moment densities, Probability Hypothesis Densities, as a prerequisite study for determining tractable implementations. (5 pages)
On the integrability of four dimensional N = 2 gauge theories in the omega background

: We continue to investigate the relationship between the infrared physics of N = 2 supersymmetric gauge theories in four dimensions and various integrable models such as Gaudin, Calogero-Moser and quantum spin chains. We prove interesting dualities among some of these integrable systems by performing diﬀerent, albeit equivalent, quantizations of the Seiberg-Witten curve of the four dimensional theory. We also discuss conformal ﬁeld theories related to N = 2 4d gauge theories by the Alday-Gaiotto-Tachikawa (AGT) duality and the role of conformal blocks of those CFTs in the integrable systems. As a consequence, the equivalence of conformal blocks of rank two Toda and Novikov-Wess-Zumino-Witten (WZNW) theories on the torus with punctures is found.
Sensitivity theory for nonlinear systems. I. Nonlinear functional analysis approach

Concepts of nonlinear functional analysis are employed to investigate the mathematical foundations underlying sensitivity theory. This makes it possible not only to ascertain the limitations inherent in existing analytical approaches to sensitivity analysis, but also to rigorously formulate a considerably more general sensitivity theory for physical problems characterized by systems of nonlinear equations and by nonlinear functionals as responses. Two alternative formalisms, labeled the ’’forward sensitivity formalism’’ and the ’’adjoint sensitivity formalism,’’ are developed in order to evaluate the sensitivity of the response to variations in the system parameters. The forward sensitivity formalism is formulated in normed linear spaces, and the existence of the Gâteaux differentials of the operators appearing in the problem is shown to be both necessary and sufficient for its validity. This formalism is conceptually straightforward and can be advantageously used to assess the effects of relatively few p.
An anisotropic hybrid non-perturbative formulation for 4D N = 2 supersymmetric Yang-Mills theories

: We provide a simple non-perturbative formulation for non-commutative four-dimensional N = 2 supersymmetric Yang-Mills theories. The formulation is constructed by a combination of deconstruction (orbifold projection), momentum cut-oﬀ and matrix model techniques. We also propose a moduli ﬁxing term that preserves lattice supersymmetry on the deconstruction formulation. Although the analogous formulation for four-dimensional N = 2 supersymmetric Yang-Mills theories is proposed also in [1], our action is simpler and better suited for computer simulations. Moreover, not only for the non-commutative theories, our formulation has a potential to be a non-perturbative tool also for the commutative four-dimensional N = 2 supersymmetric Yang-Mills theories.
The order O ( (cid:11) t (cid:11) s ) corrections to the trilinear Higgs self-couplings in the complex NMSSM

: A consistent interpretation of the Higgs data requires the same precision in the Higgs boson masses and in the trilinear Higgs self-couplings, which are related through their common origin from the Higgs potential. In this work we provide the two-loop corrections at O ( (cid:11) t (cid:11) s ) in the approximation of vanishing external momenta to the trilinear Higgs self-couplings in the CP-violating Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM). In the top/stop sector two di(cid:11)erent renormalization schemes have been implemented, the OS and the DR scheme. The two-loop corrections to the self-couplings are of the order of 10% in the investigated scenarios. The theoretical error, estimated both from the variation of the renormalization scale and from the change of the top/stop sector renormalization scheme, has been shown to be reduced due to the inclusion of the two-loop corrections.