Miracle-dz/UniFAR-FTUs huggingface dataset:
Testing and Modeling Gas Turbines Using Multisine Signals and Frequency-Domain Techniques

The frequency-domain identification of gas turbine dynamics is discussed. Models are directly estimated from engine data and used to validate linearized thermodynamic models derived from the engine physics. This work is motivated by the problems previously encountered when using time-domain methods. A brief overview of frequency-domain techniques is presented and the design of appropriate multisine test signals is discussed. Practical results are presented for the modelling of the fuel feed to shaft speed dynamics of a twin-spool engine. The gathered data are analyzed and the frequency response functions of the engine are estimated. The identification of parametric s-domain models is discussed in detail and a comparison made between the identified models and the linearized thermodynamic models. The influence of engine nonlinearities on the linear models is also examined.
DIRECT TRANSMISSION ELECTRON MICROSCOPE OBSERVATION OF ELECTROTRANSPORT IN ALUMINUM THIN FILMS

Electrotransport in thin Al strips was directly observed by transmission electron microscopy. As expected, hole formation was seen in regions where the electron flow was in the direction of increasing temperature. Hillocks and whiskers were seen to form where the electron flow was in the direction of decreasing temperature. Cine films taken of the process show the holes to grow predominantly by a transverse movement of narrow fingers which ultimately coalesce and lead to a catastrophic strip burn‐out.
Detection of HCO(+) J = 9 - 8 line emission toward Orion IRc2 - Molecular ions in hot dense gas

The HCO + J = 9→8 802.458 GHz transition was detected toward IRc2 in Orion. The line width implies that the emission originates in the low-velocity flow/doughnut most likely 10″ or less from IRc2. If the line is optically thin, the density in the line-forming region is 10 7 cm -3 or higher. If the HCO + line arises in the same ∼10″ × 20″ source as other lines with similar width, the total column density of HCO + is 3 × 10 14 cm -2 or higher, implying a line-of-sight averaged abundance 2 × 10 -9 or more
An ultra-fast data acquisition system for coherent synchrotron radiation with terahertz detectors

The recording of coherent synchrotron radiation requires data acquisition systems with a temporal resolution of tens of picosecond. This paper describes a new real-time and high-accuracy data acquisition system suitable for recording individual ultra-short pulses generated by a fast terahertz (THz) detector (e.g. YBCO, NbN, Zero Biased Schottky Diode). The system consists of a fast sampling board combined with a high data throughput readout. The first board is designed for sampling the fast pulse signals with a full width half maximum (FWHM) between a few tens to one hundred picoseconds with a minimum sampling time of 3 ps. The high data throughput board consists of a PCIe-Bus Master DMA architecture used for fast data transfer up to 3 GByte/s. The full readout chain with fast THz detectors and the acquisition system has been successfully tested at the synchrotron ANKA. An overview of the electronics system and preliminary results with multi-bunch filling pattern will be presented.
Widely tunable opto-electronic oscillator

We present here a widely tunable opto-electronic oscillator (OEO) based on an Er,Yb:glass Dual Frequency Laser (DFL) at 1.53 μm. The beatnote is stabilized with an optical fiber delay line. Compared to classical optoelectronic oscillators, this architecture does not need RF filter and offers a wide tunability. We measured a reduction of 67 dB of the phase noise power spectral density (PSD) at 10 Hz of the carrier optical fiber leading to a level of -27 dBc/Hz with only 100 m optical fiber. Moreover, the scheme offers a microwave signal tunability from 2.5 to 5.5 GHz limited by the RF components.
Ultraviolet spectroscopy of R Coronae Borealis

Observations of the hydrogen-deficient supergiant R CrB were obtained with the IUE over an interval of 54 days in order to study the nature of this star's irregular, small-amplitude variations in light. By chance, the series of observations coincided with a dip in the light intermediate between the normal fluctuations and the deep declines associated with the formation of an obscuring dust cloud. High-resolution spectra have been used to search for radial velocity variations, while low-resolution spectra yield ultraviolet light curves down to 1810 A. Both types of spectra have been analyzed for indications of temperature changes. It is found that a combination of photospheric temperature variation and variable extinction is necessary to account for the details of the observations. A simple, ad hoc, periodic model is presented in which the amount of obscuring dust varies in proportion to the drop in temperature, but at a later time, reproduces the wavelength dependence of both the amplitudes and phase shifts of the light curves. The radial velocities are consistent with pulsation being responsible for the temperature variation.
Discovery of a possible X-ray triple - 4U 1915-05

The optical counterpart of the 50 minute binary and X-ray burst source 4U 1915-05 has been identified with a 21st mag blue object. Extensive CCD photometric observations show that the optical modulation of the system defines a period of 50.4567 minutes with high precision and is thus probably the true orbital period, whereas the range of X-ray ray dip period values (49.7-50.1 minutes) reported previously are excluded. A model is described whereby the optical modulation is due to partial eclipse of the rim of the accretion disk by a low-mass companion star and the X-ray dips are due to absorption and scattering by blobs of material above and below the disk plane and with density proportional to the current mass transfer rate from the companion star. The 1 percent difference in periods may suggest that the system is a hierarchical triple with a third companion star of low-mass orbiting the binary ion in an about 2.5 day retrograde orbit. The possible origin of such a system by tidal capture in a globular cluster, since disrupted, is briefly discussed. 25 references.
On the reconstruction of obstacle using MFS from the far field data

We consider the reconstruction of an obstacle with impedance boundary in an inverse scattering problem from far-field data. Both the boundary shape and the boundary impedance are unknown. By first transforming the far field into the near field, we consider this inverse problem as the detection of a void with impedance boundary embedded in bounded homogeneous media domain G. Then we set the Dirichlet-to-Neumann boundary condition in ∂G and solve this interior boundary reconstruction problem in terms of the method of fundamental solution (MFS) with the near field on ∂G as input inversion data. For this problem, both the locations of source points and the obstacle boundary as well as the expansion coefficients of wave field are taken to be the unknowns under the framework of regularizing optimization. The property of this optimization problem such as the existence and convergence of the minimizer is analysed. Numerical examples are presented for several configurations to show the validity of our proposed scheme.
Fabrication of Raman biochip prototype by femtosecond laser micromachining

In this work, a nanoscale surface-enhanced Raman scattering (SERS) substrate is fabricated by fs laser reduction and deposition. The conductive silver microstructures are also deposited in fs laser irradiated area on the glass surfaces. Based on this approach, we integrate the microelectronic circuit and micro-Raman substrate into a microfluidic chamber and form a prototype of Raman biochip for biosensing. Enhancement of Raman signal and control of temperature of the sensor are both achieved. This technique provides a great potential for integrating microelectronics and micro-Raman sensors on a single glass chip.
Direct tunneling hole currents through ultrathin gate oxides in metal-oxide-semiconductor devices

We present a physical model to calculate the direct tunneling hole current through ultrathin gate oxides from the inversion layer of metal–oxide–semiconductor field-effect transistors. A parametric self-consistency method utilizing the triangular well approximation is used for the electrostatics of the inversion layer. For hole quantization in the inversion layer, an improved one-band effective mass approximation, which is a good approximation to the rigorous six-band effective mass theory, is used to account for the band-mixing effect. The tunneling probability is calculated by a modified Wentzel–Kramers–Brilliouin (WKB) approximation, which takes the reflections near the Si/SiO2 interfaces into account. It is found that the parabolic dispersion in the SiO2 band gap used in the WKB approximation is only applicable for hole tunneling in oxides thinner than about 2 nm and for low gate voltage. A more reasonable Freeman–Dahlke hole dispersion form with significantly improved fitting to all experimental data.
Temperature dependence of the structure factor of GeS2 glass

We have measured the temperature dependence of the first two peaks in the structure factor of GeS/sub 2/ glass. The first peak shows an increase in intensity between 300 and 523 K. The second-peak intensity is practically independent of T in this range. This anomalous behavior is similar to that found in As/sub 2/Se/sub 3/ and As/sub x/S/sub 1-x/ glasses which also appear to have a short-range order corresponding to layers.
Galactic disk kinematics traced by low-altitude stars of 55 km s−1 mean transverse velocity within 500 pc from the Sun

A set of 75 × 10 3 stars at an altitude lower than 300 pc above the galactic plane and with a 55 km/s mean transverse velocity was used to map the Galactic disk velocity field in a 500 pc radius solar neighborhood. The ellipsoidal distribution of the velocities in the galactic plane indicates an age range of 5 Gyr. A circular motion with an expansion of 21 ± 12 km/(s × kpc) was observed and suggests a nonflat rotation curve, even when the young Gould's Belt stars are removed
Electro‐optic microwave measurements in the frequency domain

A new electro‐optic system is developed to probe microwave signals on nonlinear crystals. The method uses two narrow linewidth solid state continuous wave (cw) lasers. The beat frequency between the two cw lasers is set equal to the microwave frequency plus a few MHz. The wave mixing between the beat frequency and the microwave signal is used to down convert the high frequency signal from the GHz to the MHz range where it is treated and displayed. The actual frequency bandwidth of the method is limited by the excursion between the two lasers (in our case, 50 GHz).
A Randomized Response Protocol Based on Homomorphic Encryption

The investigation which involves the respondents privacy is hard to ensure the information security. To rectify this problem, Based on Homomorphic Response Protocol (RRPBH), a novel protocol using homomorphic encrypted system is proposed in this paper. The RRPBH uses the Paillier encryption algorithm to encrypt respondents answer. Paillier algorithm has the good properties of additive homomorphism and mixed multiplicative homomorphism. We can effectively compute the sum of respondents answer with better privacy protection by this protocol.
Exploring the science, safety, and benefits of air care products: perspectives from the inaugural air care summit

Abstract Seventy-one percent of US households purchase air care products. Air care products span a diverse range of forms, including scented aerosol sprays, pump sprays, diffusers, gels, candles, and plug-ins. These products are used to eliminate indoor malodors and to provide pleasant scent experiences. The use of air care products can lead to significant benefits as studies have shown that indoor malodor can cause adverse effects, negatively impacting quality of life, hygiene, and the monetary value of homes and cars, while disproportionately affecting lower income populations. Additionally, studies have also shown that scent can have positive benefits related to mood, stress reduction, and memory enhancement among others. Despite the positive benefits associated with air care products, negative consumer perceptions regarding the safety of air care products can be a barrier to their use. During the inaugural Air Care Summit, held on 18 May 2018 in the Washington, DC, metropolitan area, multidisciplinary experts including industry stakeholders, academics, and scientific and medical experts were invited to share and assess the existing data related to air care products, focusing on ingredient and product safety and the benefits of malodor removal and scent. At the Summit’s completion, a panel of independent experts representing the fields of pulmonary medicine, medical and clinical toxicology, pediatric toxicology, basic science toxicology, occupational dermatology and experimental psychology convened to review the data presented, identify potential knowledge gaps, and suggest future research directions to further assess the safety and benefits of air care products.
Charge-coupled devices: frame adding as an alternative to long integration times and cooling

CCDs used for low light level applications require a long integration time and/or cooling to have acceptable SNR. Standard commercially available CCD cameras (e.g., for TV applications) are used with a relatively short integration time (≈1/60 s per field) and are operated at room temperature. Consequently, these cameras will have poor SNR if used for low light level applications. The addition of successive frames from a standard CCD camera for the improvement of the SNR is considered here. We show, using a simple model, that a range of signal levels (as low as a few millilux) exists for which frame addition is a viable alternative to long integration times and cooling.
Confirmation of solar cycle-dependent intermediate-degree p-mode frequency shifts

Results of intercomparisons of seven different sets of frequencies of intermediate-degree p-modes obtained at several different locations between 1981 and 1989 are presented. It is shown that the frequency shifts exhibited by all of these intermediate-degree p-modes are consistent with the intermediate-degree frequency shifts presented by Libbrecht and Woodward (1990) and also with the low-degree frequency shifts presented by Elsworth et al. (1990). It is also shown that these frequency shifts correlate with solar cycle-dependent changes in sunspot number, area, and irradiance. Unbinned and binned differences between 1984 Mount Wilson Observatory and revised 1981 South Pole frequencies are illustrated.
Power balancing for a new class of non-linear systems and stabilization of RLC circuits

In this paper the method of power shaping, as recently introduced for the stabilization of non-linear RLC circuits, is generalized to a larger class of systems showing similarities (and important differences) with the class of port-controlled Hamiltonian systems. Other than for port-controlled Hamiltonian systems, the stabilization of these new systems is not stymied by a ‘dissipation obstacle’ and, in fact, every power-shaping controller is power balancing as well. It is shown that the power-shaping controller can be realized as a port-controlled Hamiltonian system connected by means of a gyrator to the plant. The theoretical results are applied to the class of non-linear RLC circuits described by Brayton–Moser's equations, and a physical implementation of the controllers in terms of standard electrical circuit elements is given.
Electronic transport properties of free-base tape-porphyrin molecular wires studied by self-consistent tight-binding calculations

We investigated by theoretical calculations the electronic states and the transport properties of one of the oligoporphyrin molecular wires, the free-base tape-porphyrins. Inside these molecules the adjacent building blocks, referred to as porphyrin macrocycles, are linked by three conjugating C-C bonds aligned in parallel. We found that the origin of the extremely small highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gaps of these molecules is the strong coupling between the unoccupied $\ensuremath{\pi}$ orbitals of each macrocycle. Then we considered the molecular bridges where these porphyrin molecules are bridged between the aluminum electrodes. We found that the conductances have large values and that the current increases nearly in proportion to the applied bias. These features are explained by the strong hybridization of the HOMO with the electrode wave functions and by the wide bandwidth of the tape porphyrins. Finally we studied the current distribution inside the tape-porphyrin wire. The current is found to flow in an anisotropic way, i.e., it seems to flow along the spatial distribution of the HOMO of the tape porphyrins, reflecting the strong hybridization of the HOMO with the electrode wave functions.
Analytic Properties of the Quantum Corrections to the Second Virial Coefficient

The usefulness of the perturbation expansion and the Wigner‐Kirkwood expansion of the quantum‐mechanical partition function is discussed for various interaction potentials. It is shown that, contrary to what is expected from the Wigner‐Kirkwood expansion, quantum‐mechanical diffraction corrections at high temperature to the classical partition function may involve nonanalytic forms of ℏ2. This occurs when the second‐order perturbation term is finite in the classical limit, and the interaction potential has a cusp or singularity in any derivative. The second‐order perturbation term is evaluated exactly for the exponential, screened Coulomb, and square barrier potentials, and the nonanalytic form (ℏ2)½ is found. For potentials more singular than 1/r at the origin, the diffraction corrections are analytic in ℏ2. A new method of deriving the Wigner‐Kirkwood expansion from the perturbation expansion is given. The method allows one to subtract off any order of the perturbation expansion which may be evaluated se.
Influence of sputtering mechanisms on the preferred orientation of aluminum nitride thin films

This article presents a study of the influence of the sputtering parameters on the preferred orientation of polycrystalline aluminum nitride thin films. Aluminum nitride films were grown by rf reactive sputtering of an aluminum target in an N2/Ar gas mixture for different values of the deposition parameters: total pressure, nitrogen content in the discharge gas, and substrate bias voltage. The preferred orientation of the films was analyzed by x-ray diffraction. Films with different preferred orientations were obtained, ranging from c-axis oriented films to films with the c axis tilted by up to 61.6° from the substrate normal. The different mechanisms influencing the preferred orientation of the films have been considered, especially the transfer of energy to the adatoms on the substrate by particle bombardment. An analysis of the relation between the deposition parameters and the crystal orientation has allowed us to determine the relative importance of the different particles in the supply of energy to .
Correspondences for Hecke Rings and (Co-)Homology Groups on Smooth Compactifications of Siegel Modular Varieties

We show that the Hecke rings act on the l-adic cohomology groups of suitable non-singular proiective toroidal compactiﬁcations of the higher dimensional modular varieties. We extend the ﬁxed point theory of Lefschetz to the correspondences for the Hecke rings on those compactiﬁcations. We treat here the Siegel modular case.
Analysis of one-dimensional rough surface scattering based on bidirectional reflectance distribution function model

Through in-depth analysis of the scattering properties of a one-dimensional random rough surface, a method to calculate the spatial bidirectional reflectance distribution function (BRDF) characteristics of a randomly rough surface is proposed. The scattering characteristics of an electrically large rough surface can be substituted by combination of subsection electromagnetic fields. The radar cross-section (RCS), which is transformed from the BRDF, is compared with numerical results from the Method of Moment (MoM). The agreement of the results verifies that this method could calculate the electromagnetic scattering field efficiently and straightforwardly. Moreover, the resulting combined fields from the BRDF of subsections in the rough surface show a good match with the entire scattering field of a whole surface, which indicates that a large electrically rough surface could be feasibly and effectively substituted with the combination of scattering elements using the BRDF method and the statistical method.
On finite W-algebras for Lie algebras and superalgebras

The finiteW-algebras are certain associative algebras associated to a complex semi-simple or reductive Lie algebra g and a nilpotent element e of g. Due to recent results of I. Losev, A. Premet and others, finite W-algebras play a very important role in description of primitive ideals. In the full generality, the finiteW-algebras were introduced by A. Premet. It is a result of B. Kostant that for a regular nilpotent (principal) element e, the finiteW-algebra coincides with the center of U(g). Premet’s definition makes sense for a simple Lie superalgebra g = g¯0 g¯1 in the case when g¯0 is reductive, g admits an invariant super-symmetric bilinear form, and e is an even nilpotent element. We show that certain results of A. Premet can be generalized for classical Lie superalgebras. We consider the case when e is an even regular nilpotent element. The associated finiteW-algebra is called principal. Kostant’s result does not hold in this case. This is joint work with V. Serganova.
Generalization of the Bremmer coupling series

An operator formalism is developed to expand the acoustic wave field in a multi‐dimensionally smoothly varying medium, generated by a source localized in space and time, into a sum of constituents each of which can be interpreted as a wave that has traveled up and down with respect to a direction of preference a definite number of times. This expansion is a generalization of the Bremmer coupling series. The condition of smoothness of the medium relates to the width of the signature of the source in the configuration. Both the existence and the convergence (in the weak sense) of the expansion are discussed. The operator calculus involved leads to a natural generalization of the concept of slowness surface to multi‐dimensionally smoothly varying media. The operator associated with the corresponding generalized vertical slowness induces the full one‐way wave operator in the type of media under consideration. In addition, a wavefield decomposition operator as well as an interaction operator that couples the d.
A Study on the Sensitivity of a Spin Valve with Conetic-Based Free Layers

An exchange-biased spin valve with Conetic-based free layers of Co90Fe10, Co90Fe10/Conetic and Conetic was investigated. The spin valve with the Co90Fe10 free layer showed the highest giant magnetoresistance (GMR) ratio of 4% but showed the lowest normalized sensitivity of 0.02 Oe-1. The GMR ratio of 3% and the normalized sensitivity of 0.07 Oe-1 were obtained for the spin valve with the Co90Fe10/Conetic free layer after annealing. The spin valve having the Conetic free layer showed softer magnetic properties and well-defined smaller anisotropy than the other spin valves. Though the spin valve showed the lowest GMR of 0.4% after annealing, it showed the highest normalized sensitivity of 0.14 Oe-1. Our study shows that further improvement in MR response of spin valves with Conetic-based free layers can make a spin valve sensor promising for detecting extremely low fields.