Miracle-dz/UniFAR-FTUs huggingface dataset:
Polytropic relationship in interplanetary magnetic clouds

Interplanetary magnetic clouds are expanding MHD configurations characterized by strong magnetic fields, large rotations of the field vector, and low ion temperatures. In this paper we present high time resolution data from the ISEE 3 and IMP 8 spacecraft on the magnetic field and the proton and electron populations in a number of magnetic clouds. Our objective is to study aspects of the thermodynamics of magnetic clouds and the relation between their thermodynamic and magnetic structures. Our analysis suggests the following features of the thermodynamics of magnetic clouds: (1) The electron and ion populations are not in thermal equilibrium with each other, the electron temperature, Te, being in general up to an order of magnitude higher than the proton temperature, Tp. The temperature ratio Te/Tp in these magnetic clouds is larger than typical values of this quantity in the solar wind at comparable heliocentric distances. (2) For the proton component we find that a polytropic law with γp in the range 1.1 < γp < 1.3 is probably adequate to describe the relation between Tp and density. (3) For the electrons (E < 1.18 keV) the energetics are likewise governed by a polytropic law. Unlike the protons the polytrope that describes the electrons has an index that is less than unity, implying anticorrelation between Te and the number density. For the two clouds analyzed where electron data are available, γe ≈ 0.48 ± 0.2. (4) As a corollary of case 3, the variation of Te with density in magnetic clouds is the reverse of that generally found in the inner heliosphere. (5) Electron temperatures are well correlated with the magnetic field strength, the highest values being reached where the field strength maximizes. We interpret these experimental findings along the following lines. While the magnetic field of the cloud expands, the ions are cooled (though not so effectively as in the adiabatic case (γad = 5/3), indicating some exchange of energy with the ambient solar wind). In contrast, since γe < 1, when the density drops as a result of expansion, Te increases and, consequently, a temperature difference develops between the two species. The hot electrons are trapped by the magnetic field in the core of the magnetic cloud. If magnetic clouds originate in the region near the Sun where Tp < Te, the subsequent expansion accentuates this temperature disparity further. Such conditions are favorable for the generation of ion acoustic waves.
Surface phase diagram for Cr 2 O 3 ( 0001 ) : Ab initio density functional study

Surface phases of ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}(0001)$ as a function of ambient oxygen pressure and temperature were computed by ab initio density-functional theory for a solid surface. The surface can be $(1\ifmmode\times\else\texttimes\fi{}1)$ or $(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})$ Cr terminated, $(1\ifmmode\times\else\texttimes\fi{}1)$ O terminated, and $(1\ifmmode\times\else\texttimes\fi{}1)$ or $(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})$ $(\mathrm{O}=\mathrm{Cr})$ terminated. This is the first theory of the chromyl $(\mathrm{O}=\mathrm{Cr})$ termination. The terminations critically depend on the environment, i.e., on the temperature and on the ambient oxygen partial pressure. The first-principles phase diagram is compared with a substantial number of experimental observations of surface phases.
Polarization and the ratio of total-to-selective extinction

Relationships between extinction and polarization parameters are explored using ultraviolet (ANS and IUE), visual, and infrared data along the same lines of sight. In particular, the well-known empirical relationship between polarization and extinction, p less than or equal to 9.0E(B - V), has been reexamined using lines of sight for which R(V), the ratio of total-to-selective extinction, is known. It is found that the amount of polarization per unit extinction p/A(V) is related to R(V) such that the maximum observed value of p/A(V) is smaller for large R(V). This implies that large grains are not efficient at producing polarization, which may be atributed to a reduced axial ratio or to less efficient alignment. 53 references.
High‐power mode‐locked semiconductor lasers using flared waveguides

We describe the use of flared waveguide diode lasers for obtaining increased output power under mode‐locked operation. The flared waveguide expands the optical mode from a narrow region which gives a single lateral optical mode, to a wider multimode region for higher pulse saturation energy. Flared gain and flared absorber section geometry devices are compared to devices with conventional uniform waveguides. Using flared gain section devices, improvements in both pulse energy (6.8 pJ) and pulsewidth (3.3 ps) were measured compared to uniform waveguide devices. Peak powers of over 2 W are obtained, which, to our knowledge, is the highest peak power obtained directly from mode‐locked single stripe diode lasers.
Volume degeneracy of the typical cell and the chord length distribution for Poisson-Voronoi tessellations in high dimensions

This paper is devoted to the study of some asymptotic behaviors of Poisson-Voronoi tessellation in the Euclidean space as the space dimension tends to ∞. We consider a family of homogeneous Poisson-Voronoi tessellations with constant intensity λ in Euclidean spaces of dimensions n = 1, 2, 3, …. First we use the Blaschke-Petkantschin formula to prove that the variance of the volume of the typical cell tends to 0 exponentially in dimension. It is also shown that the volume of intersection of the typical cell with the co-centered ball of volume u converges in distribution to the constant λ−1(1 − e−λu ). Next we consider the linear contact distribution function of the Poisson-Voronoi tessellation and compute the limit when the space dimension goes to ∞. As a by-product, the chord length distribution and the geometric covariogram of the typical cell are obtained in the limit.
The extended surface forces apparatus. Part I. Fast spectral correlation interferometry

This article describes details of the operation and performance of fast spectral correlation interferometry, which allows for considerably improved operation of the surface forces apparatus. Up to 150 interference fringes can be simultaneously tracked over a wide spectral range, leading to considerably more precise and simultaneous extraction of multiple optical quantities, over a greatly extended distance range. When used for surface-separation measurement, a precision of 25 pm is readily achievable over a distance ranging from 0 to >10 μm. Data acquisition rates are also considerably improved, allowing for dynamic measurements. Automated actuation of optical deflectors introduces a multidimensional scanning capability to the optical probe with a lateral resolution of 1 μm. The entire process is computer controlled and features unattended batch processing of complex measurements. This publication illustrates experimental setup, methodology, measurements, and detailed error calculation for a selection of .
Equatorial Solitary Waves. Part 2: Envelope Solitons

Abstract Via the method of multiple scales, it is shown that the time and space evolution of the envelope of wave packets of weakly nonlinear, strongly dispersive equatorial waves is governed by the Nonlinear Schrodinger equation. The diverse phenomena of this equation—envelope solitons, sideband instability, FPU recurrence and more—is briefly reviewed. Which of the alternatives occurs is determined largely by the relative signs of the coefficients of the dispersive and nonlinear terms in the Nonlinear Schrodinger equation which, for a given latitudinal mode, are functions of a single nondimensional parameter, the zonal wavenumber k. Gravity waves propagating toward the east form solitary waves and are subject to sideband instability only for large k. The mixed Rossby-gravity wave has solitons only in a range of intermediate k. For waves with group velocities toward the west, the physics is much more complicated because these waves have an infinite number of second harmonic resonances and long wave/short .
CONSIDERING SAWDUST AS A POTENTIAL RAW MATERIAL FOR CLIMATE CHANGE MITIGATION IN INDOOR ENVIRONMENT

The object of the study is sawdust as a potential raw material for climate change mitigation in the indoor environment. The method of the mixture was used to determine the specific heat capacity of the sawdust sample, while its thermal conductivity was determined using the Lee disc method. The results of the study showed that the specific heat capacity of the sawdust is 54.9271 J·g –1 ·K –1 and that of thermal conductivity is 0.12 W/m·K. The implication of the results is that Sawdust needs about 54.9271 J·g –1 ·K –1 to raise its unit mass by 1 ° C and a comparably very low thermal conductivity of 0.12 W/m·K. Sawdust can be used as a composite material for roofing, and ceilings to drastically reduce the rate at which the heat energy from the sun is transferred into the indoor environment and consequently reduce the effects of climate change on the indoor environment. Sawdust that is not properly managed or disposed can pose serious problems to aquatic and terrestrial ecosystems, fuel fire outbreaks and health problems such as severe allergic reactions. Therefore, discovering other reuse options for sawdust will reduce the problems it poses to the environment.
Numerical simulations of mantle convection: time-dependent, three-dimensional, compressible, spherical shell

Abstract We describe nonlinear time-dependent numerical simulations of whole mantle convection for a Newtonian, infinite Prandtl number, anelastic fluid in a three-dimensional spherical shell for conditions that approximate the Earth's mantle. Each dependent variable is expanded in a series of 4,096 spherical harmonics to resolve its horizontal structure and in 61 Chebyshev polynomials to resolve its radial structure. A semiimplicit time-integration scheme is used with a spectral transform method. In grid space there are 61 unequally-spaced Chebyshev radial levels, 96 Legendre colatitudinal levels, and 192 Fourier longitudinal levels. For this preliminary study we consider four scenarios, all having the same radially-dependent reference state and no internal heating. They differ by their radially-dependent linear viscous and thermal diffusivities and by the specified temperatures on their isothermal, impermeable, stress-free boundaries. We have found that the structure of convection changes dramatically a.
Modelling of the kinetics and parametric behaviour of a copper vapour laser: Output power limitation issues

A self-consistent computer model was used to simulate the plasma kinetics (radially resolved) and parametric behaviour of an 18 mm bore (6 W) copper vapour laser for a wide range of optimum and non-optimum operating conditions. Good quantitative agreement was obtained between modelled results and experimental data including the temporal evolution of the 4p2P3/2, 4s2 2D5/2 and 4s22D3/2 Cu laser level populations derived from hook method measurements. The modelled results show that the two most important parameters that affect laser behaviour are the ground state copper density and the peak electron temperature Te. For a given pulse repetition frequency (prf), maximum laser power is achieved by matching the copper atom density to the input pulse energy thereby maintaining the peak Te at around 3 eV. However, there is a threshold wall temperature (and copper density) above which the plasma tube becomes thermally unstable. At low prf (<8 kHz), this thermal instability limits the attainable copper density (and.
The Impedance Boundary Value Problem for the Helmholtz Equation in a Half‐Plane

We prove unique existence of solution for the impedance (or third) boundary value problem for the Helmholtz equation in a half-plane with arbitrary L∞ boundary data. This problem is of interest as a model of outdoor sound propagation over inhomogeneous flat terrain and as a model of rough surface scattering. To formulate the problem and prove uniqueness of solution we introduce a novel radiation condition, a generalization of that used in plane wave scattering by one-dimensional diffraction gratings. To prove existence of solution and a limiting absorption principle we first reformulate the problem as an equivalent second kind boundary integral equation to which we apply a form of Fredholm alternative, utilizing recent results on the solvability of integral equations on the real line in [5].
High-temperature elasticity and viscosity of GexSe1−xglasses in the transition range

The viscous-flow behavior and temperature dependence of the elastic moduli of chalcogenide glasses from the germanium-selenium system were studied by means of homemade high-temperature indentation setup and resonant-frequency technique (1-10 kHz), respectively, for temperatures between 0.8 and 1.2×Tg. The softening rates, both in the elastic and in the viscous-flow regimes, were correlated to network destructuration or reorganization events in the light of previously reported high-temperature neutron-scattering data. The concomitant change of Poisson's ratio (ν) and the thermodynamic parameters of the thermally activated viscous-flow process were characterized and provide a new basis for the understanding of the sources for the softening in the transition range. The temperature dependence of ν suggests weak changes of the network cross-linking degree at large Ge contents. On the contrary, in the case of a-Se, a steep fragmentation of the structural units is inferred from the ν(T) data, and the flow process is accompanied by a huge entropy change (activation entropy at saddle point). The entropy contribution at Tg (Tg ×dSa) represents more than 50% of the activation enthalpy for flow (dHa) and increases with the selenium content. Hence the free activation energy (dGa) is much smaller than apparent activation energy as derived from viscosity data.
Associative classification with a new condenseness measure

Associative classification (AC) is a branch of data mining that utilizes association rules (ARs) for classification. ARs are extracted from databases that satisfy some statistical criteria such as minimal support. However, in some practical applications, useful ARs may be found among infrequent, but closely related, itemsets that are filtered out by high minimal support. In this study, a new measure, named “condenseness,” is presented for evaluating whether infrequent ruleitems that are filtered out by minimal support can form strong ARs for classification. For an infrequent ruleitem, the condenseness is the average of lift of all ARs that can be generated from the ruleitem. A ruleitem with a high condenseness means that its elements are closely related and can serve for AC even if it does not have high support. Based on the concept of condenseness, a new associative classifier is developed and presented – condensed association rules for classification (CARC). CARC generates ARs using a modified Apriori algorithm and develops new strategies of rule inference. With the condenseness measure and strategies for rule inference, more useful ARs can be produced and improve the effectiveness of association classification. Empirical evidences show that CARC mitigates the problems caused by setting too high/low minimal support and has a better performance on classification.
Nanowire array based photonic crystal devices

Photonic crystals consisting of semiconductor nanowire arrays grown using a metal catalyzed vapor-liquid-solid (VLS) method are excellent candidates for photonic elements and devices, such as micro-cavities, due to the high dielectric constant contrast and high aspect ratio. In addition, it is easy to control the crystal structure by patterning the metal catalysis, and the versatility of composition of nanowires (including II-VI, III-V and ternary III-V) makes the integration of optical components in diversified wavelength ranges possible. Here we use a Plane-Wave-Expansion (PWE) method and Finite Difference Time Domain (FDTD) technique toinvestigate the optical properties of nanowire based photonic crystals. It is found that arrays consisting of nanowires with radius at or below the edge of the effective single-wire confining range for a stand alone Fabry-Perot cavity can still form a high-Q value cavity with single mode operation. Our results will help to extend the concept of the-state-of-art 1-D distributed bragg reflector (DBR) and distributed feedback (DFB) lasers into 2-D ones with a working range from ultraviolet to near infrared.
Dielectric Response and Electric-Field-Induced Metastable State in an Organic Conductor β(meso-DMBEDT-TTF)2PF6

Dielectric response and nonlinear conduction are studied in an organic conductor β-( meso -DMBEDT-TTF) 2 PF 6 , which undergoes the metal–insulator transition caused by the checkerboard-type charge ordering (CCO). The formation of the long-range CCO (LR-CCO) was observed as a sudden increase in the dielectric constant below 70 K. Below 70 K, the I – V curve shows a remarkable negative differential resistance with a non-monotonous voltage drop, and its nonlinearity survives up to about 100 K. Time-resolved sample voltage data shows a steep drop followed by a transient plateau and a further drop into the most conductive state. The former steep voltage drop may cause the negative differential resistance in the I – V curve, while the transient plateau implies a metastable state induced by the electric field.
A straight gravitational image in Abell 2390 - A striking case of lensing by a cluster of galaxies

Photometry and spectroscopy are presented for a very linear arclike object found in the center of the rich cluster of galaxies Abell 2390 (z = 0.231). The main feature in its spectrum is an emission line at 7130 A that exists all along the arc. The identification of this emission line as Forbidden O II (3727 A) leads to a redshift of 0.913 for the structure. This is the third arc candidate confirmed spectroscopically as a gravitationally lensed background galaxy. 27 refs.
High energy electron radiation effect on Ni/4H-SiC SBD and Ohmic contact

The Ni/4H-SiC Schottky barrier diodes (SBDs) and transfer length method (TLM) test patterns of Ni/4H-SiC Ohmic contacts were fabricated, and irradiated with 1 MeV electrons up to a dose of 3.43 × 1014 e/cm−2. After radiation, the forward currents of the SBDs at 2 V decreased by about 50%, and the reverse currents at −200 V increased by less than 30%. Schottky barrier height (oB) of the Ni/4H-SiC SBD increased from 1.20 eV to 1.21 eV under 0 V irradiation bias, and decreased from 1.25 eV to 1.19 eV under −30 V irradiation bias. The degradation of oB could be explained by the variation of interface states of Schottky contacts. The on-state resistance (Rs) and the reverse current increased with the dose, which can be ascribed to the radiation defects in bulk material. The specific contact resistance (ρc) of the Ni/SiC Ohmic contact increased from 5.11 × 10−5 Ω. cm2 to 2.97 × 10−4 Ω. cm2.
Presentation and Application of Tunable Reciprocal/Nonreciprocal Metamaterial Transmission Line Based on Edge-Guided Mode

Abstract This article proposes a tunable composite right-/left-handed transmission line consisting of a transversely magnetized ferrite substrate periodically loaded by microstrip inductors. The gapless transition between the left- and right-handed bands (balanced response) is the main characteristic of this structure. This composite right-/left-handed transmission line is proposed in both reciprocal and nonreciprocal versions. Based on periodic structure analysis, the dispersion relation is estimated theoretically and validated numerically by the finite-element method in the reciprocal case. Theoretical and numerical results demonstrate the tunability of the proposed structures by changing the DC bias magnetic field applied to the ferrite. To demonstrate the applicability of the proposed structure, a tunable nonreciprocal phase shifter is designed.
Thermal conductivity measurement of individual CdS nanowires using microphotoluminescence spectroscopy

We present a scheme to measure the thermal conductivity of individual nanowires using temperature-dependent and microphotoluminescence spectroscopy. The CdS nanowires suspended over trenches in silicon substrate were excited with a focused laser beam in confocal configuration. The photoluminescence at the laser spot gave a measure of the local temperature rise determined by the excitation laser intensity and the thermal conductance of the nanowires. By obtaining the temperature gradient across the nanowire and the length of the suspended segment, the thermal conductivity of CdS nanowires with diameters in the range of 200–400 nm was extracted to be in the range of 4.9–6.2 W/m K.
Simultaneous measurements of scalar and velocity field evolution in turbulent crossflowing jets

Simultaneous planar laser-induced fluorescence (PLIF) and particle image velocimetry (PIV) yield measurements of two-dimensional jet fluid concentration and velocity fields in turbulent crossflowing jets. The jet-to-crossflow velocity ratio is $r = 5.7$ and the jet exit Reynolds number is approximately 5000. The measurements are focused on the developing region of the flow. Two flow configurations are studied, one in which the jet nozzle is flush with the tunnel wall and the other where the nozzle protrudes into the uniform region of the tunnel flow. The jet nozzle in both cases is a simple pipe. The averaged scalar and velocity fields show a strong similarity in growth rates and centreline decay rates between the two nozzle configurations when using the centreline downstream coordinate $s$. This suggests that the flow geometry is less important than, for example, jet exit conditions in determining the initial flow development. The velocity fields show indications of jet-like scaling in the near field, and a possible approach to wake-like scaling in the far field. These canonical scalings are less evident in the scalar fields. Results are presented for the averaged scalar variance, $\langle C^{'2}\rangle$, the scalar flux components, $\langle u_{i}'C'\rangle$, the turbulent normal stresses, $\langle u^{\prime 2}\rangle$ and $\langle v^{\prime 2}\rangle$, and the turbulent shear stress, $\langle u'v'\rangle$. We also discuss the resolution issues bearing on the determination of small-scale fluctuations.
Photoluminescence from SiO2 films containing Si nanocrystals and Er: Effects of nanocrystalline size on the photoluminescence efficiency of Er3+

SiO2 films containing Si nanocrystals (nc-Si) and Er were prepared and their photoluminescence (PL) properties were studied. The samples exhibited PL peaks at 0.8 and 1.54 μm, which could be assigned to the electron-hole recombination in nc-Si and the intra-4f transition in Er3+, respectively. Correlation between the intensities of the two PL peaks was studied as functions of the size of nc-Si, Er concentration, excitation power and excitation wavelength. It was found that the 1.54 μm PL of Er3+ is strongly enhanced by incorporating nc-Si in films. Furthermore, the intensity of the 1.54 μm peak was found to depend strongly on the size of the incorporated nc-Si.
Tomographic Imaging of the Sun's Interior

A new method is presented of determining the three-dimensional sound-speed structure and flow velocities in the solar convection zone by inversion of the acoustic travel-time data recently obtained by Duvall and coworkers. The initial inversion results reveal large-scale subsurface structures and flows related to the active regions, and are important for understanding the physics of solar activity and large-scale convection. The results provide evidence of a zonal structure below the surface in the low-latitude area of the magnetic activity. Strong converging downflows, up to 1.2 km s-1, and a substantial excess of the sound speed are found beneath growing active regions. In a decaying active region, there is evidence for the lower than average sound speed and for upwelling of plasma.