Miracle-dz/UniFAR-FTUs huggingface dataset:
A novel algorithm in the FMCW microwave liquid level measuring system

The structure of a frequency modulated continuous wave (FMCW) microwave liquid level radar system was introduced and the FMCW radar ranging principle was discussed. A fast frequency estimation algorithm (FFEA) based on fast Fourier transform (FFT) technique, which can achieve high ranging accuracy and better computational efficiency, was proposed to obtain the distance information from the radar echo signal. The high-speed signal processor DSP is suitable for the real-time signal processing, and can be used to linearize the frequency sweep of VCO. The simulation results indicated that FFEA owned high accuracy as compared with the FFT method and required much less computational load as compared with zoom FFT.
Extended Ly-alpha emission associated with 3C 294

Optical, IR, and radio observations of the powerful radio source 3C 294, which is surrounded by a large cloud of ionized gas, are presented. The galaxy is faint in the rest-frame UV, yet has a near-IR luminosity that is typical of radio galaxies at redshifts of order two. In contrast to the large extent of the ionized gas, the K-band image is quite compact. The emission-line cloud is closely aligned with the radio source axis and has an ionization state indicative of ionization by a nonstellar source. The velocity field of the gas has both large ordered motions and large turbulent components. The total mass required to keep the gas bound to the system is comparable to present-day massive galaxies and their halos. The velocity fields of the high-ionization lines are systematically different from Ly-alpha in a manner that is not easily understood. 88 refs.
Class fields by Shimura reciprocity

We apply the Shimura reciprocity law to determine when values of mod-ularr functions of higher level can be used to generate Hubert class fields of an imagi-naryy quadratic fields. In addition, we show how to find the corresponding polynomial inn these cases. This yields a proof for conjectural formulas of Morain and Yui-Zagier forr such polynomials. RÉSUMÉ. On applique la loi de réciprocité de Shimura pour decider quand les valeurs dess fonctions modulaires de haut niveau peuvent étre utilisées pour engendrer le corps dee classes de Hubert d'un corps quadratique imaginaire. Lorsque c'est le cas, nous montronss aussi comment trouver le polynöme correspondant. Cela donne une preuve dee certaines formules conjecturales de Morain et Zagier relatives a ces polynömes.
Theory of the almost-highest wave. Part 2. Matching and analytic extension

Most methods of calculating steep gravity waves (of less than the maximum height) encounter difficulties when the radius of curvature R at the crest becomes small compared with the wavelength L, or some other typical length scale. This paper describes a new method of calculation valid when R/L is small. For deep-water waves, a parameter ε is defined as equal to q/2½c0, where q is the particle speed at the wave crest, in a frame of reference moving with the phase speed c. Hence ε is of order (R/L)½. Three zones are distinguished: (1) an inner zone of linear dimensions ε2L near the crest, where the flow is described by the inner solution found previously by Longuet-Higgins & Fox (1977); (2) an outer zone of dimensions O(L) where the flow is given by a perturbed form of Michell's solution for the highest wave; and (3) a matching zone of width O(L). The matching procedure involves complex powers of ε. The resulting expression for the square of the phase velocity is found to be \[ c^2 = (g/k)\{1.1931-1.18\epsilon^3\cos(2.143\ln \epsilon + 2.22)\} \] (see figures 5a, b), which is in remarkable agreement with independent calculations based on high-order series. In particular, the existence of turning-points in the phase velocity as a function of wave height is confirmed. Similar expressions, valid to order ε3, are found for the wave height, the potential and kinetic energies and the momentum flux or impulse of the wave. The velocity field is extended analytically across the free surface, revealing the existence of branch-points of order ½, as predicted by Grant (1973).
Ion production by positron impact on H2O

The energy distributions of positrons scattered around 0° from H2O have been measured in coincidence with the remnant ions (H2O+, OH+ and H+) at 100 eV and 153 eV incident energies. The maxima of the distributions (d2σ/dE+dΩ) associated with the production of OH+ and H+ are about 5–10 times smaller than that for H2O+. At both incident energies, a small shoulder has been observed at ∼28 eV in the energy loss spectra associated with H2O+ production possibly arising from a shake-up band associated with the 2a1 orbital. The branching ratios for the H+ and HO+ fragments are also presented.
Analysis of human factors on urban heat island and simulation of urban thermal environment in Lanzhou city, China

Abstract. Urban heat island (UHI) effect is a global phenomenon caused by urbanization. Because of the number and complexity of factors contributing to the urban thermal environment, traditional statistical methods are insufficient for acquiring data and analyzing the impact of human activities on the thermal environment, especially for identifying which factors are dominant. The UHI elements were extracted using thermal infrared remote sensing data to retrieve the land surface temperatures of Lanzhou city, and then adopting an object-oriented fractal net evolution approach to create an image segmentation of the land surface temperature (LST). The effects of urban expansion on the urban thermal environment were quantitatively analyzed. A comprehensive evaluation system of the urban thermal environment was constructed, the spatial pattern of the urban thermal environment in Lanzhou was assessed, and principal influencing factors were identified using spatial principal component analysis (SPCA) and multisource spatial data. We found that in the last 20 years, the UHI effect in Lanzhou city has been strengthened, as the UHI ratio index has increased from 0.385 in 1993 to 0.579 in 2001 and to 0.653 in 2011. The UHI expansion had a spatiotemporal consistency with the urban expansion. The four major factors that affect the spatial pattern of the urban thermal environment in Lanzhou can be ranked in the following order: landscape configuration, anthropogenic heat release, urban construction, and gradient from man-made to natural land cover. These four together accounted for 91.27% of the variance. A linear model was thus successfully constructed, implying that SPCA is helpful in identifying major contributors to UHI. Regression analysis indicated that the instantaneous LST and the simulated thermal environment have a good linear relationship, the correlation coefficient between the two reached 0.8011, highly significant at a confidence level of 0.001.
Improved multi-position calibration for inertial measurement units

Calibration of inertial measurement units (IMU) is carried out to estimate the coefficients which transform the raw outputs of inertial sensors to meaningful quantities of interest. Based on the fact that the norms of the measured outputs of the accelerometer and gyroscope cluster are equal to the magnitudes of specific force and rotational velocity inputs, respectively, an improved multi-position calibration approach is proposed. Specifically, two open but important issues are addressed for the multi-position calibration: (1) calibration of inter-triad misalignment between the gyroscope and accelerometer triads and (2) the optimal calibration scheme design. A new approach to calibrate the inter-triad misalignment is devised using the rotational axis direction measurements separately derived from the gyroscope and accelerometer triads. By maximizing the sensitivity of the norm of the IMU measurement with respect to the calibration parameters, we propose an approximately optimal calibration scheme. Simulations and real tests show that the improved multi-position approach outperforms the traditional laboratory calibration method, meanwhile relaxing the requirement of precise orientation control.
Propagation factors controlling mean field strength on urban streets

Calculation of mean field strength for urban mobile radio has been made on a ray-theoretical basis assuming an ideal city structure with uniform building heights. The result shows that building height, street width, and street orientation as well as mobile station antenna height are controlling propagation parameters in addition to the ordinary factors. The major theoretical characteristics agree approximately with experimental data including conventional empirical predictions. This suggests a way of theoretically predicting mean field strength in an urban area.
Discrete Log-Aesthetic Filter

AbstractThe aesthetic curves include the logarithmic (equiangular) spiral, clothoid, and involute curves. Although most of them are expressed only by an integral form of the tangent vector, it is possible to interactively generate and deform them and they are expected to be utilized for practical use of industrial and graphical design. However, the curvature of a log-aesthetic curve segment must be monotonically increasing or decreasing and a strong constraint as a function of arc length is imposed on its curvature. For geometrical design, it is desirable not to impose strong constraints on the designer’s activity, to let him/her design freely and to embed the properties of the log-aesthetic curves for complicated curves with both increasing and decreasing curvature. Hence we develop discrete filters named discrete log-aesthetic filters to fair a sequence of points with noises and to fit it locally to log-aesthetic curves. Furthermore we extend them for surfaces.
Turbulence structure in thermal convection and shear-free boundary layers

This paper is a study of turbulence near rigid surfaces, in the absence of any mean shear. Different sources of turbulence are considered, including thermal convection and grid turbulence. It is shown that, if a rigid boundary is introduced into the flow, then for short times the linear theory of Hunt & Graham (1978) reveals the common structure of these flows near the boundary, if the parameters used are the rate of energy dissipation per unit mass ε and the distance z from the surface. Over longer times nonlinear effects develop, such as large eddies straining smaller eddies near the boundary. Some new estimates are suggested here and compared with the computations of Biringen & Reynolds (1981) and experiments of Thomas & Hancock (1977). It is shown that calculations based on the linear theory agree well with many measurements of the vertical profiles of turbulence in thermal convection layers, including those of the vertical variance, the low-frequency end of the spectrum of the vertical turbulence (w), the integral scale of w, and two-point cross-correlations of w. (The latter was a prediction, subsequently tested by atmospheric measurements.) Some discussion of the reasons for this agreement are suggested. The observations of the effects of mean-velocity gradients near the surface are also shown to be consistent with the theoretical arguments proposed here.
High‐resolution bent‐crystal spectrometer for the ultrasoft x‐ray region

A multichannel vacuum Bragg‐crystal spectrometer has been developed for high‐resolution measurements of the line emission from tokamak plasmas in the wavelength region between 4 and 25 A. The spectrometer employs a bent crystal in Johann geometry and a microchannel‐plate‐intensified photodiode diode array. The instrument is capable of measuring high‐resolution spectra (λ/Δλ≊3000) with fast time resolution (4 ms per spectrum) and good spatial resolution (3 cm). The spectral bandwidth is Δλ/λ0=15% at λ0=8 A. A simple tilt mechanism allows access to different wavelength intervals. In order to illustrate the utility of the new spectrometer, time‐ and space‐resolved measurements of the n=3–2 spectrum of selenium from the Princeton Large Torus tokamak plasmas are presented. The data are used to determine the plasma transport parameters and to infer the radial distribution of fluorinelike, neonlike, and sodiumlike ions of selenium in the plasma. The new ultrasoft x‐ray spectrometer has thus enabled us to demonst.
Raman Spectroscopy for Clinical Oncology

Cancer is one of the leading causes of death throughout the world. Advancements in early and improved diagnosis could help prevent a significant number of these deaths. Raman spectroscopy is a vibrational spectroscopic technique which has received considerable attention recently with regards to applications in clinical oncology. Raman spectroscopy has the potential not only to improve diagnosis of cancer but also to advance the treatment of cancer. A number of studies have investigated Raman spectroscopy for its potential to improve diagnosis and treatment of a wide variety of cancers. In this paper the most recent advances in dispersive Raman spectroscopy, which have demonstrated promising leads to real world application for clinical oncology are reviewed. The application of Raman spectroscopy to breast, brain, skin, cervical, gastrointestinal, oral, and lung cancers is reviewed as well as a special focus on the data analysis techniques, which have been employed in the studies.
Boundary value problems for even order nonlinear ordinary differential equations

We outline an operator-theoretic method for proving the existence of solutions of boundary value problems where the nonlinearity satisfies a Nagumo condition. In this note we explain the ideas by considering a particular fourth order problem. The method involves (i) converting the boundary value problem to an "alternative problem" [2] ; (ii) inducing a splitting of the integral operator in the alternative problem by splitting the original differential operator [3] ; and (iii) applying degree theory. Let S be the Hubert space L [0, 1] with the inner product and norm denoted by < , > and II • II respectively. Let H[0, 1] be the Hilbert space of all functions x(t) such that x(t) and its first (n 1) derivatives are absolutely continuous and x\t) E L [0, 1].
DFT calculations of atoms and molecules in Cartesian grids

Density functional theory (DFT) has emerged as one of the most versatile and lucrative approaches in electronic structure calculations of many-electron systems in past four decades. Here we give an account of the development of a variational DFT method for atoms and molecules completely in a Cartesian grid. The non-relativistic Kohn–Sham equation is solved by using an LCAO-MO ansatz. Atom-centered localized basis set, electron density, molecular orbitals, two-body potentials are directly constructed on the grid. We adopt a Fourier convolution method for classical Coulomb potentials by making an Ewald-type decomposition technique in terms of short- and long-range interactions. It produces quite accurate and competitive results for various properties of interest, such as component energy, total energy, ionization energy, potential energy curve, atomization energy, etc. Both local and non-local functionals are employed for pseudopotential as well as full calculations. While most results are offered in a uniform grid, initial exploratory attempts are made in a non-uniform grid, which can significantly reduce the computational overhead. This offers a practical, viable alternative to atom-centered grid-based implementations, currently exploited by the majority of programs available world-wide.
Robust Estimation and Hypothesis Testing of Linear Contrasts in Analysis of Covariance with Stochastic Covariates

Abstract Estimators of parameters are derived by using the method of modified maximum likelihood (MML) estimation when the distribution of covariate X and the error e are both non-normal in a simple analysis of covariance (ANCOVA) model. We show that our estimators are efficient. We also develop a test statistic for testing a linear contrast and show that it is robust. We give a real life example.
Raman study of incommensurately modulated calaverite (AuTe2)

Abstract Raman spectra of incommensurately modulated AuTe2 are presented. The large number of observed Raman active modes indicates a strong influence of the incommensurability on the dynamical properties. The resulting spectra are discussed in terms of the selection rules derived using the superspace symmetry of AuTe2
Correction of nonlinearity in one-frequency optical interferometry

The nonlinearity of one-frequency optical interferometry with quadrature fringe detection is the result of a number of factors including polarization mixing, unequal gain of detectors, imbalanced beams and lack of quadrature. An elliptical least-squares fitting technique to correct the nonlinearity is presented in this paper. Experimental results demonstrate that a nonlinearity-free condition can be achieved and the stability of the interferometer set-up in our laboratory is better than nm over 2.5 h.
Description and evaluation of nuclear masses based on residual proton-neutron interactions

In this paper we study the residual proton-neutron interactions and make use of the systematics of these interactions to describe experimental data of nuclear masses and to predict some of the unknown masses. The odd-even effect staggering of the residual proton-neutron interaction between the last proton and the last neutron is found and argued in terms of pairing interactions. Two local mass relations, which work very accurately for masses of four neighboring nuclei, are discovered. The accuracy of our predicted masses for medium and heavy nuclei is competitive with that of the AME2003 extrapolations, with the virtue of simplicity.
Fast Single Image Dehazing via Multilevel Wavelet Transform based Optimization

The quality of images captured in outdoor environments can be affected by poor weather conditions such as fog, dust, and atmospheric scattering of other particles. This problem can bring extra challenges to high-level computer vision tasks like image segmentation and object detection. However, previous studies on image dehazing suffer from a huge computational workload and corruption of the original image, such as over-saturation and halos. In this paper, we present a novel image dehazing approach based on the optical model for haze images and regularized optimization. Specifically, we convert the non-convex, bilinear problem concerning the unknown haze-free image and light transmission distribution to a convex, linear optimization problem by estimating the atmosphere light constant. Our method is further accelerated by introducing a multilevel Haar wavelet transform. The optimization, instead, is applied to the low frequency sub-band decomposition of the original image. This dimension reduction significantly improves the processing speed of our method and exhibits the potential for real-time applications. Experimental results show that our approach outperforms state-of-the-art dehazing algorithms in terms of both image reconstruction quality and computational efficiency. For implementation details, source code can be publicly accessed via this http URL.
Origin of short–lived radionuclides

This paper reviews the evidence for short–lived radionuclides in the early Solar System and critically evaluates models for their origin. Radionuclides with half–lives of less than 50 Myr for which firm and consistent evidence has been found are 10Be, 26Al, 41Ca, 53Mn, 60Fe, 107Pd, 129I and 182Hf. The oldest Solar System objects, calcium–aluminium–rich inclusions (CAIs), contained 10Be, 26Al, 41Ca and 53Mn on formation. We discuss whether a spallation or stellar origin for the radionuclides is more likely, and conclude that the initial presence of short–lived radionuclides in CAIs can be most easily explained if these formed by spallation reactions close to the protosun.
Comparison of Linear, Nonlinear and Semiparametric Mixed‐effects Models for Estimating HIV Dynamic Parameters

The potency of antiretroviral agents in AIDS clinical trials can be assessed on the basis of an early viral response such as viral decay rate or change in viral load (number of copies of HIV RNA) of the plasma. Linear, parametric nonlinear, and semiparametric nonlinear mixed‐effects models have been proposed to estimate viral decay rates in viral dynamic models. However, before applying these models to clinical data, a critical question that remains to be addressed is whether these models produce coherent estimates of viral decay rates, and if not, which model is appropriate and should be used in practice. In this paper, we applied these models to data from an AIDS clinical trial of potent antiviral treatments and found significant incongruity in the estimated rates of reduction in viral load. Simulation studies indicated that reliable estimates of viral decay rate were obtained by using the parametric and semiparametric nonlinear mixed‐effects models. Our analysis also indicated that the decay rates estimated by using linear mixed‐effects models should be interpreted differently from those estimated by using nonlinear mixed‐effects models. The semiparametric nonlinear mixed‐effects model is preferred to other models because arbitrary data truncation is not needed. Based on real data analysis and simulation studies, we provide guidelines for estimating viral decay rates from clinical data. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and upconversion luminescence of N-doped graphene quantum dots

A hydrothermal approach was developed for the synthesis of N-doped graphene quantum dots (N-GQDs) by cutting N-doped graphene. The N-GQDs obtained have a N/C atomic ratio of ca. 5.6% and diameter of 1–7 nm. The photoluminescence (PL) properties of the N-GQDs were investigated. It was found that the N-GQDs possess bright blue PL and excellent upconversion PL properties.
Wave-Induced Light-Field Fluctuations in the Sea

Irradiance fluctuations in the natural underwater light field close to the sea surface have an amplitude that is of the same order of magnitude as the mean irradiance. A principal source of these fluctuations, differential refraction by surface waves, is examined in this paper, and some experimental data obtained at an experimental site in the Bight of Abaco, Bahamas, are presented. A first-order single-ray theory is developed and the predictions of this theory are compared with the data. The theory identifies five refractive effects, the most important of which is the focusing and defocusing of light beams by fluctuations of surface curvature.
A Possible Companion to Proxima Centauri

We report Hubble Space Telescope observations that provide evidence for a companion to Proxima Centauri (Gl 551), the closest star to the Sun. Data acquired with the Faint Object Spectrograph (FOS), used as a coronagraphic camera, show excess light that can be interpreted as being from a substellar object within 0. ″5 of Proxima Cen. Two observations of Proxima Cen separated by 103 days indicate a point source (or a feature) superposed on the wing of the point-spread function in the FOS images. This feature moves relative to the aperture, and on the plane of the sky. Comparisons with other FOS images of stars acquired using the coronagraphic mode reveal no comparable features or evidence that this feature can be explained by any instrumental anomaly. If this feature denotes a companion to Proxima Cen, it has an apparent separation corresponding to ∼0.5 AU at Proxima Cen and is ≈7 mag fainter than Proxima Cen in the bandpass of the FOS red detector. The small apparent separation could result from a highly eccentric orbit, which could project a close companion. Alternately, the small separation could imply a short (∼1 yr) period. Further coronagraphic observations, using the Space Telescope Imaging Spectrograph, the Near-Infrared Camera and Multiobject Spectrometer, or some other instrumentation, are needed to verify this tentative result.