Miracle-dz/UniFAR-FTUs huggingface dataset:
A Survey of Radio Recombination Lines Toward the Galactic Center

Observations at 14 positions in the direction of the galactic center region show H159 alpha (1.621 GHz) hydrogen rccombination lines over an extended area. The lines do not originate under conditions of LTE. Comparison of one of the spectra with a neutralhydrogen absorption profile taken in the same direction shows a coincidence of features. The data is best interpreted as emission from a region with electron temperature of 20 deg K and an electron density of 3 cm/sup - 3/ lying along the line of sight to the galactic center. This model is also consistent with the observations of diffuse H157 alpha and H166 alpha line emission from the inner regions of the Galaxy. (auth)
Gradient and counter-gradient scalar transport in turbulent premixed flames

In premixed turbulent combustion, the modelling of the turbulent flux of the mean reaction progress variable remains somewhat controversial. Classical gradient transport assumptions based on the eddy viscosity concept are often used while both experimental data and theoretical analysis have pointed out the existence of countergradient turbulent diffusion. Direct numerical simulation (DNS) is used in this paper to provide basic information on the turbulent flux of and study the occurrence of counter-gradient transport. The numerical configuration corresponds to twoor three-dimensional premixed flames in isotropic turbulent flow. The simulations correspond to various flame and flow conditions that are representative of flamelet combustion. They reveal that different flames will feature different turbulent transport properties and that these differences can be related to basic dynamical differences in the flame-flow interactions: counter-gradient diffusion occurs when the flow field near the flame is dominated by thermal dilatation due to chemical reaction, whereas gradient diffusion occurs when the flow field near the flame is dominated by the turbulent motions. The DNS-based analysis leads to a simple expression to describe the turbulent flux of , which in turn leads to a simple criterion to delineate between the gradient and counter-gradient turbulent diffusion regimes. This criterion suggests that the occurrence of one regime or the other is determined primarily by the ratio of turbulence intensity divided by the laminar flame speed, and by the flame heat release factor, τ ≡ (Tb — Tu )/Tu , where Tu and Tb are respectively the temperature within unburnt and burnt gas. Consistent with the Bray-Moss-Libby theory, counter-gradient (gradient) diffusion is promoted by low (high) values and high (low) values of τ. DNS also shows that these results are not restricted to the turbulent transport of . Similar results are found for the turbulent transport of flame surface density, Σ. The turbulent fluxes of and Σ are strongly correlated in the simulated flames and counter-gradient (gradient) diffusion of always coincides with counter-gradient (gradient) diffusion of Σ.
Modified braid equations for SOq(3) and noncommutative spaces

General solutions of the RTT equation with a maximal number of free parameters in the specrtal decomposition of vector SOq(3) R matrices are implemented to construct modified braid equations (MBE). These matrices conserve the given, standard, group relations of the nine elements of T, but are not constrained to satisfy the standard braid equation (BE). Apart from q and a normalization factor our R contains two free parameters, instead of only one such parameter for deformed unitary algebras studied in a previous paper [Math. QA/0009178] where the nonzero right hand side of the MBE had a linear term proportional to (R(12)−R(23)). In the present case the rhs is, in general, nonlinear. Several particular solutions are given (Sec. II) and the general structure is analyzed (Appendix A). Our formulation of the problem in terms of projectors yields also two new solutions of standard (nonmodified) braid equation (Sec. II) which are further discussed (Appendix B). The noncommutative three-spaces obtained by i.
What causes social media users to engage and mimic virtual influencers? The role of self-congruity

Influencer marketing has been widely utilized in marketing communication. With the growing interest in virtual influencers, this study aims to investigate why social media users would interact with virtual influencers. The research model was developed based on the self-congruity theory. The data were obtained by questionnaires distributed to social media users using judgmental sampling (respondents were above 18 years old and actively used Instagram within the past six months). The questionnaire was posted on social media, and 230 responses were collected and analyzed using a covariance-based structural equation. Influencer-brand fit was found to have a weak direct effect on engagement (γ = 0.158, p &lt; 0.05), but insignificant direct effect on mimicry desire (γ = 0.160, p &gt; 0.05). Value homophily significantly affects both engagement and mimicry desire directly (β = 0.338 and β = 0.622, p &lt; 0.01). Moreover, value homophily was found to fully mediate the virtual influencer-brand fit/mimicry desire relationship (B = 0.546, p &lt; 0.01) and partially mediate the relationship of virtual influencer-brand fit/engagement (B = 0.229, p &lt; 0.01). However, the mediating effect of mimicry desire on the virtual influencer-brand fit/engagement relationship was found to be non-significant (B = 0.065, p &gt; 0.05). This study contributes to influencer marketing by highlighting value homophily as the most significant factor explaining why consumers respond to a virtual influencer when used as a message source in marketing communication.
Noncommutative Residues and Manifolds with Conical Singularities

Abstract For every singular point on a manifold with conical singularities a trace can be constructed on the “Cone Algebra with Asymptotics” introduced by B. -W. Schulze. Each of them vanishes on operators supported in the interior and is therefore different from the noncommutative residue established by Wodzicki. On the ideal of operators with zero conormal symbol, however, we find another trace which coincides with the noncommutative residue in the interior. All these traces are shown to be essentially unique on a slightly extended version of the cone algebra.
Formation of the First Stars by Accretion

The process of star formation from metal-free gas is investigated by following the evolution of accreting protostars with emphasis on the properties of massive objects. The main aim is to establish the physical processes that determine the upper mass limit of the first stars. Although the consensus is that massive stars were commonly formed in the first cosmic structures, our calculations show that their actual formation depends sensitively on the mass accretion rate and its time variation. Even in the rather idealized case in which star formation is mainly determined by Ṁ acc, the characteristic mass scale of the first stars is rather uncertain. We find that there is a critical mass accretion rate Ṁ crit ≃ 4 × 10-3 M☉ yr-1 that separates solutions with Ṁ acc < Ṁcrit in which objects with mass ≫100 M☉ can form, provided there is sufficient matter in the parent clouds, from others (Ṁacc > Ṁcrit) where the maximum mass limit decreases as Ṁ acc increases. In the latter case, the protostellar luminosity reaches the Eddington limit before the onset of hydrogen burning at the center via the CN cycle. This phase is followed by a rapid and dramatic expansion of the radius, possibly leading to reversal of the accretion flow when the stellar mass is about 100 M☉. Under a realistic time-dependent accretion rate that starts at high values (~10-2 M☉ yr-1) and decreases rapidly in the high-mass regime (M* ≳ 90 M☉), the evolution follows the case of Ṁ acc < Ṁcrit and accretion can continue unimpeded by radiation forces. Thus, the maximum mass is set by consideration of stellar lifetimes rather than by protostellar evolution. In this case, the upper limit can be as high as ~600 M☉. We consider also the sensitivity of the results to the presence of heavy elements with abundances in the range Z = 5 × 10-5 to 5 × 10-3 Z☉. The main evolutionary features of protostars are similar to those of metal-free objects, except that the value of Ṁ crit increases for metal-enriched protostars. Since the accretion rate is lower in a slightly polluted environment, the condition Ṁ acc < Ṁcrit is expected to be more easily met. We find that for metallicities below ~10-2 Z☉, where radiation forces onto dust grains in the flow are negligible, a slightly metal-rich gas favors continued accretion and the formation of very massive stars.
Cosmological implications of ROSAT observations of groups and clusters of galaxies

We have used ROSAT PSPC observations to determine the total gravitating mass in a sample of 9 groups and clusters of galaxies. All of these clusters (spanning a range in gas temperatures of 1.0 to 8 keV) have mass‐to‐light ratios of 100–150 M⊙/L⊙. This indicates that rich clusters do not contain any more dark matter than individual galaxies. We also find that the ratio of total mass‐to‐luminous mass (hot gas and stars) uniformly decreases from galaxies, to groups, to clusters. Only 10% of the gravitating mass in galaxies and groups can be accounted for while 30% is observable in rich clusters. This indicates that the universe becomes ‘‘brighter’’ on larger scales not ‘‘darker. ’’
Memory effect of Al-rich AlN films synthesized with rf magnetron sputtering

Al-rich AlN thin film, which is deposited onto n-type Si substrate by radio frequency sputtering of Al target in an argon and N2 gas mixture, can exhibit a large memory effect as a result of charge trapping in the Al nanoparticles/nanoclusters embedded in the AlN matrix. For the metal-insulator-semiconductor structure with a 60nm Al-rich AlN thin film, a voltage of −15V applied to the metal electrode for 10−6s causes a flatband voltage shift of ∼1.5V. Both electron trapping and hole trapping are possible, depending on the polarity of the applied voltage. In addition, whether the electron trapping or the hole trapping is the dominant process also depends on the charging time and the magnitude of the voltage. The Al-rich AlN thin films provide the possibility of memory applications with low cost.
Potential-energy curves of the CH radical molecule under spin-orbit coupling

Potential energy curves for the ground and excited electronic states of the CH radical molecule were calculated employing spin-orbit multiconfiguration quasi-degenerate perturbation theory (SO-MCQDPT). The results of our present SO-MCQDPT calculation for the CH radical molecule indicate that the ground electronic state of X 2Π splits into lower X1 2Π1/2 and higher X2 2Π3/2Ω states. The excited electronic state of a 4Σ– splits into lower a1 4Σ–1/2 and higher a24Σ–3/2, and the excited electronic state of A 2Δ splits into lower A1 2Δ3/2 and higher A2 2Δ5/2. The spin-orbit splittings for the 2S+1Λ states X 2Π, a 4Σ–, and A 2Δ are determined to be 25.963, 0.016, and 0.992 cm–1, respectively. The splittings are in good agreement with the experimental data for X 2Π and A 2Δ , and there are no experimental data for a 4Σ–. The potential-energy curves for all calculated bound states of CH are fitted to an analytical potential-energy function in the large range of R = 0.06–0.55 nm, from which accurate spectroscopic .
SPH Modeling of Solid Boundaries Through a Semi-Analytic Approach

Abstract: This paper presents a general semi-analytic approach for modeling solid boundaries in the SPH method: boundaries are here considered as a material continuum with a suitable distribution of velocity and pressure; their contributions to each term of the SPH mass and momentum equations can be expressed in terms of a suitable integral extended to the part of the sphere of influence of the particle delimited by the boundary surface. Analytical details with reference to a slightly compressible viscous Newtonian fluid in three dimensions are given. The validity of the method is checked by comparing the obtained numerical results with available experimental data in a benchmark flow case.
Three-Dimensional Variational Data Assimilation Experiments for a Heavy Rainfall Case in the Downstream Yangtze River Valley Using Automatic Weather Station and Global Positioning System Data in Southeastern Tibetan Plateau

A severe rainfall event occurred in the downstream Yangtze River Valley (YRV) during 28–30 June 2009. This study focused on the role of the “key sensitive area” (KSA) in the southeastern edge of the Tibetan Plateau (TP) in transporting water vapor downstream. The characteristics of water-vapor transport from KSA and the relation with the summer rainfall event were first investigated using the National Centers for Environmental Prediction Final Operational Global Analysis data and conventional observations. The observations included temperature, specific humidity (q), and surface pressure that are all from the automatic weather stations (AWS) over TP; precipitable water vapor (PWV) from the Global Positioning System (GPS) stations over TP; and rainfall from rain gauge measurements in YRV. The results showed high correlations between variables (i.e., q and PWV) observed over KSA and the summer rainfall in YRV, with a lagged time of 48–72 h, suggesting that the former is a good earlywarning signal for the latter. To confirm the importance of KSA and its impact on the rainfall in the downstream YRV, the observations from the AWS and GPS of the New Integrated Observational System over TP were assimilated into the Advanced Research Weather Research and Forecast model with 30-km mesh using three-dimensional variational method. A set of sensitivity experiments were also conducted during a different summer, namely, June 2008, and Threat Score is used to evaluate the rainfall forecast skill. The results showed that the assimilation of observations from AWS and GPS in Corresponding author: Xiangde Xu, State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China E-mail: cep99@cams.cma. gov.cn ©2014, Meteorological Society of Japan Journal of the Meteorological Society of Japan Vol. 92, No. 5 484
Analysis of a homogenous and heterogeneous stylized half core of a CANDU reactor

Abstract The MCNPX (Monte Carlo N-Particle Transport Code System) code has been used for modeling and simulation of a half core of CANDU (CANada Deuterium-Uranium) reactor, both homogenous and heterogeneous model for the reactor core are designed. The fuel is burnt in normal operation conditions of CANDU reactors. Natural uranium fuel is used in the model. The multiplication factor for homogeneous and heterogeneous reactor core is calculated and compared during fuel burnup. The concentration of both uranium and plutonium isotopes are analysed in the model. The flux and power distributions through channels are calculated.
Study of the Ordered Magnetic State of Copper Formate Tetrahydrate by Antiferromagnetic Resonance

A brief account of antiferromagnetic-resonance (AFMR) measurements in single crystals of monoclinic Cu${(\mathrm{HCOO})}_{2}$. 4${\mathrm{H}}_{2}$O has been reported, and it was shown that a model of weak ferromagnetism of the easy-plane type is not consistent with the data. This paper presents in detail the AFMR data and includes calculations of the AFMR modes and the magnetization based on assuming that Cu${(\mathrm{HCOO})}_{2}$4${\mathrm{H}}_{2}$O is very nearly an antiferromagnet in zero magnetic field. AFMR measurements have been made between 1.4 and 15\ifmmode^\circ\else\textdegree\fi{}K. Resonance transitions have been observed at 9 GHz, from 32 to 36 GHz, from 50 to 80 GHz, and from 107 to 124 GHz in magnetic fields up to 26 kOe. From the angular dependence of the field positions of the resonance transitions, a set of "principal axes" ${a}^{\ensuremath{'}\ensuremath{'}}b{c}^{\ensuremath{'}\ensuremath{'}}$ of the magnetic crystal have been determined. ${a}^{\ensuremath{'}\ensuremath{'}}$, the antiferromagnetic axis, is shown to be 8.5\ifmmode^\circ\else\textdegree\fi{} away from the $a$ axis toward the $c$ axis. The AFMR modes and the magnetization have been calculated on a two-sublattice model, based on a bilinear exchange interaction, assuming ${a}^{\ensuremath{'}\ensuremath{'}}$ as the antiferromagnetic axis, $b$ as the intermediate axis, and ${c}^{\ensuremath{'}\ensuremath{'}}$ as the hard axis. This calculation is an extension of one by Cinader by including the hard-plane anisotropy and an anisotropic antisymmetric $g$-tensor. It is found that a magnetic field (perpendicular to ${a}^{\ensuremath{'}\ensuremath{'}}$) larger than a critical field induces a weak ferromagnetic state. The calculation also shows that both antisymmetric exchange and the antisymmetric Zeeman interaction contribute to the effective canting fields. For the ${c}^{\ensuremath{'}\ensuremath{'}}$-axis case, the calculations are in good agreement (except for a constant gap in the low-frequency mode above 5.3 kOe) with the data and an effective canting field ${{H}_{\mathrm{DM}}}^{\ensuremath{'}}=84$ kOe is obtained. For the $b$ axis, the experiment indicates an instability in the antiferromagnetic axis at 5.3 kOe. The calculations also suggest an instability in the antiferromagnetic axis if a second effective canting field ${{h}_{\mathrm{DM}}}^{\ensuremath{'}}$ is negative; however, a quantitative fit to the AFMR modes has not been possible. A simplified calculation for the ${a}^{\ensuremath{'}\ensuremath{'}}$ axis is in fair agreement with some of the ${a}^{\ensuremath{'}\ensuremath{'}}$-axis data. The temperature dependence of the low-frequency zero-field mode is found to deviate substantially from the prediction of the molecular field approximation. A temperature-dependent contribution to the AFMR line-width of ${T}^{3.3\ifmmode\pm\else\textpm\fi{}0.2}$ is found.
Soliton-like solutions of higher order wave equations of the Korteweg-de Vries type

In this work we study second and third order approximations of water wave equations of the Korteweg–de Vries (KdV) type. First we derive analytical expressions for solitary wave solutions for some special sets of parameters of the equations. Remarkably enough, in all these approximations, the form of the solitary wave and its amplitude-velocity dependence are identical to the sech2 formula of the one-soliton solution of the KdV. Next we carry out a detailed numerical study of these solutions using a Fourier pseudospectral method combined with a finite-difference scheme, in parameter regions where soliton-like behavior is observed. In these regions, we find solitary waves which are stable and behave like solitons in the sense that they remain virtually unchanged under time evolution and mutual interaction. In general, these solutions sustain small oscillations in the form of radiation waves (trailing the solitary wave) and may still be regarded as stable, provided these radiation waves do not exceed a nume.
Entrainment Rate and Size of Entrained Droplets in Annular Two-Phase Flow

The flowrate and size of entrained droplets were measured in upward annular flow of air and liquid. The rate of droplets entrained from the liquid film to the gas core was derived taking into account the rate of droplets transferred from the gas core onto the liquid film. The size distribution of the droplets in the gas core was approximated by a gamma distribution and empirical equations were proposed for the mean diameter of the droplets in terms of the conditions of gas flow and the surface tension.
Magnetic origin of enhanced top exchange biasing in Py/IrMn/Py multilayers

In a substrate/ferromagnetic/antiferromagnetic/ferromagnetic trilayer, the exchange coupling occurring at the bottom ferromagnetic/antiferromagnetic interface is always found to be weaker than the one of the top antiferromagnetic/ferromagnetic interface. In spite of many reported results, in this paper we show that this effect does not exclusively depend on changes of the crystallographic quality or the roughness of the antiferromagnetic layer, or on magnetic interactions between the two ferromagnetic layers. On the contrary, this effect is associated with the different domain patterns on the two sides of the antiferromagnetic layer. Indeed, the upper interface of this layer appears unbiased after multilayer growth but it acquires a larger field biasing than the lower interface during the subsequent in-field annealing. Thus, in opposition to established growth conditions, applying a magnetic field during the multilayer growth does not appear to be the best way to get the highest exchange coupling.
Towards an improvement on prediction accuracy in JPEG-LS

Among a context of three pixels, the present JPEG-LS produces predicted values based on whether a vertical edge or a horizontal edge is detected. When a diagonal edge exists, however, experiments and observation reveal that such a prediction will generate large predictive errors. By applying the triangle inequality to the analysis of predictive templates in JPEG-LS, we propose a diagonal-edge detection scheme to reduce the predictive error and hence provide an improvement on the prediction accuracy. Experiments are carried out to test the proposed scheme for a group of sample images. In comparison with the current JPEG-LS prediction, our scheme produces lower prediction errors, in terms of both MSE measurement and visual comparison of error images.
Stellar winds driven by super-Eddington luminosities

On construit plus de 100 modeles de l'ecoulement externe stable et a symetrie spherique d'un gaz d'une etoile de 1,4 M ○. avec une enveloppe d'helium pur et une luminosite depassant parfois la limite d'Eddington. Application aux etoiles a neutrons
Measurement of the anisotropy constant of antiferromagnets in metallic polycrystalline exchange biased systems

A method for the measurement of the anisotropy constant of the antiferromagnet (AF) KAF in exchange biased systems has been developed. This has been achieved by measurement of the median blocking temperature ⟨TB⟩ of a CoFe∕IrMn bilayer. In thermal activation-free conditions, this is the temperature at which equal volumes of the AF are oriented in opposite senses. Hence, for a grain size dependent model, the critical volume for thermal activation at this point is equal to the median volume of the grain size distribution. A value of (5.5±0.5)×106erg∕cc has been obtained at room temperature for a 4nm thick IrMn layer.
High-resolution upwind scheme for vortical-flow simulations

One of the high-resolution upwind schemes called "MUSCL with Roe's average" is applied to vortical flow simulations. Two examples are considered. One is the leading-edge, separation-vortex flow over a strake-delta wing. The other is a high angle-of-attack supersonic flow over a space-plane-like configuration. The comparison with the central-difference solutions indicates that the present upwind scheme is less dissipative and thus has better resolution for the vortical flows. Thus, it is concluded that the use of proper unwind schemes is recommended for vortical flow simulations at a high Reynolds number, and verification of computed result is especially important for vortical-flow simulations.
Modified superconductor–insulator–normal metal–insulator– superconductor Josephson junctions with high critical parameters

Superconductor–insulator–normal metal–insulator–superconductor (SINIS) and SINS′NIS junctions (here S, I, and N denote superconductor, insulator, and normal metal, respectively) were fabricated using Nb/Al technology and characterized at low temperatures. It is shown that asymmetric SINIS junctions with different transparency of the two tunnel barriers may have higher critical voltages than analogous symmetric junctions at 4.2 K. Also, SINS′NIS junctions were fabricated and investigated. If the thickness of the S′ layer is very thin, these junctions have quasiparticle current–voltage characteristics similar to those of conventional SINIS junctions at 4.2 K, but the Josephson critical current densities, and therefore, the critical voltages, are much higher than the corresponding values for conventional SINIS junctions.