Miracle-dz/UniFAR-FTUs huggingface dataset:
Slip-flow in microchannels of non-circular cross sections

Closed form solutions are presented for fully developed pressure driven slip-flow in straight microchannels of uniform noncircular cross-sections. To achieve this goal, starting from the general solution of the Poisson's equation in the cylindrical coordinate, a least-squares-matching of boundary values is employed for applying the slip boundary condition at the wall. Then the application of boundary conditions for three different types of cross sections is examined. While the model is general enough to be extended to almost any arbitrary cross section, microchannels of polygonal (with circular as a limiting case), rectangular, and rhombic cross sections are analyzed in this study. The results are then successfully compared to the existing data in the literature.
Post-glitch relaxation following the ninth glitch of the Vela pulsar

The relaxation observed by McCulloch, Hamilton, & Deshpande (1993) following the ninth observed glitch of the Vela pulsar provides a stringent test of the phenomenological vortex creep theory developed by Alpar et al. (1993) to explain post-glitch behavior following its previous eight glitches. Their theory predicts that the relaxation following the ninth glitch would be characterized by linear response with short time scale relaxation times, 10 hr, 3.2 days, and 33 days, respectively, a long-term torque linear in time, and a permanent offset in the frequency derivative. We present the results of an analysis of the post-glitch behavior following the ninth glitch and find excellent agreement with these predictions
Electro-optically tunable photonic crystals

We report on electro-optical modulation with a sub-1-V sensitivity in a photonic crystal slab waveguide resonator which contains a nanostructured second-order nonlinear optical polymer. The electro-optical susceptibility in the core was induced by high electric-field poling. A square lattice of holes carrying a linear defect was transferred into the slab by electron-beam lithography and reactive ion etching, creating a photonic crystal slab-based resonator. Applying an external electric modulation voltage to electrodes leads to a linear electro-optical shift of the resonance spectrum and thus to a modulation of the transmission at a fixed wavelength based on the electronic displacement polarization in a noncentrosymmetric medium (Pockels effect). This effect is therefore inherently faster than other reported electro-optic modulation effects in nanophotonics.
Quantum theory of the diplon

The work of Heisenberg Majorana and Wigner seems to show that the behaviour of protons and neutrons and their interaction in the nucleus may be described by the ordinary methods of quantum mechanics. It is of particular interest to study the simplest nuclear system, i. e . , the diplon, which almost certainly consists of a proton and a neutron. In dealing with such a two-body problem, the wave equation can be rigorously solved if the forces are known, and this problem therefore has the same importance for nuclear mechanics as the hydrogen atom has for atomic theory. The force acting between a proton and a neutron has been investigated by Wigner ( loc. cit. ) who showed that in order to understand the high mass defect of He4 compared with H2 one must assume interaction forces with a range much smaller than the radius of H2. Without knowing about these forces more than the binding energy of H2, one can, then, investigate quantitatively the behaviour of H2 against various perturbations.
Luminescence from stacking faults in gallium nitride

A direct correlation has been established between stacking faults in a-plane GaN epilayers and luminescence peaks in the 3.29–3.41 eV range. The structural features of the stacking faults were determined by diffraction-contrast transmission electron microscopy, while the optical emission characteristics were observed by highly spatially resolved monochromatic cathodoluminescence. The studies were performed in the exact same regions of thinned foils. We find that stacking faults on the basal plane are responsible for the strong emission at ∼3.14eV. Luminescence peaks at ∼3.33 and ∼3.29eV are associated with the presence of stacking faults on prismatic a planes and partial dislocations at the stacking fault boundaries, respectively.
FORMATION AND EVOLUTION OF A MULTI-THREADED SOLAR PROMINENCE

We investigate the process of formation and subsequent evolution of prominence plasma in a filament channel and its overlying arcade. We construct a three-dimensional time-dependent model of an intermediate quiescent prominence suitable to be compared with observations. We combine the magnetic field structure of a three-dimensional sheared double arcade with one-dimensional independent simulations of many selected flux tubes, in which the thermal nonequilibrium process governs the plasma evolution. We have found that the condensations in the corona can be divided into two populations: threads and blobs. Threads are massive condensations that linger in the flux tube dips. Blobs are ubiquitous small condensations that are produced throughout the filament and overlying arcade magnetic structure, and rapidly fall to the chromosphere. The threads are the principal contributors to the total mass, whereas the blob contribution is small. The total prominence mass is in agreement with observations, assuming reasonable filling factors of order 0.001 and a fixed number of threads. The motion of the threads is basically horizontal, while blobs move in all directions along the field. We have generated synthetic images of the whole structure in an Hα proxy and in two EUV channels of the Atmospheric Imaging Assembly instrument on board Solar Dynamics Observatory, thus showing the plasma at cool, warm, and hot temperatures. The predicted differential emission measure of our system agrees very well with observations in the temperature range log T = 4.6–5.7. We conclude that the sheared-arcade magnetic structure and plasma behavior driven by thermal nonequilibrium fit the abundant observational evidence well for typical intermediate prominences.
The Dark Mass Concentration in the Central Parsec of the Milky Way

We report ∼1″ resolution K-band (2 μm) imaging spectroscopy of the central parsec of our Galaxy. The derived radial velocities for 223 early- and late-type stars probe the nuclear mass distribution to spatial scales of 0.1 pc. We find a statistically very significant increase of projected stellar velocity dispersion from about 55 km s−1 at p ∼ 5 pc to 180 km s−1 at p ∼ 0.1 pc. The stars are also rotating about the dynamic center. The late-type stars follow general Galactic rotation, while the early-type stars show counter-rotation. Fitting simultaneously the observed projected surface densities and velocity dispersions, we derive the intrinsic volume densities and radial velocity dispersions as a function of distance from the dynamic center for both types of stars. We then derive the mass distribution between 0.1 and 5 pc from the Jeans equation assuming an isotropic velocity field. Our analysis requires a compact central dark mass of 2.5 − 3.2 × 106 M☉ at 6 − 8 σ significance. The dark mass has a density of 109 M☉ pc−3 or greater and a mass to 2 μm luminosity of ≥ 100. The increase in mass-to-luminosity ratio can be reduced but not eliminated even if extreme anisotropic velocity destributions are considered. The dark mass cannot be a cluster of solar mass remnants (such as neutron stars). It is either a compact cluster of 10–20 M☉ black holes or a single massive black hole.
High Angular Resolution Observations of the (J, K) = (1, 1), (2, 2), and (3, 3) Transitions of Ammonia in NGC 253

The nearby starburst galaxy NGC 253 was mapped in the ammonia ( J,K ) = (1 , 1), (2 , 2), and (3 , 3) lines in the 23 GHz region with the Very Large Array. The angular resolutions were about 4 (cid:2)(cid:2) × 3 (cid:2)(cid:2) . The distributions of the three lines were different from one another. The (1 , 1) and (3 , 3) lines were distributed along the bar mainly at the northeastern and southwestern regions from the center, but the (2 , 2) line is distributed mainly at two clumps in the southwestern region from the center. In addition, the (1 , 1) line showed absorption at the central region. The obtained rotational temperatures were < 15–28K (lower limit), depending on the clumps. The ammonia distributions are generally consistent with estimates from our single-dish results already published. The distributions of ammonia were compared with those of continuum and several other molecular lines.
A Search for Double-Mode RR Lyrae Stars in the Globular Cluster M68

Published observations of 23 c-type RR Lyr stars in M68 have been analyzed in a search for double-mode pulsators (RRd stars). There are at least seven and possibly as many as 10 RRd stars with primary periods in the range of 0.39-0.41 d. Reliable values of both the fundamental and first overtone periods have been obtained for one of the stars (V3). The double-mode pulsation mass for V3, using the King Ia (Y = 0.299, Z = 0.001) mass calibration of Cox et al. (1983), is 0.64 + or - 0.005 solar mass. 43 refs.
Dynamics of Bilaterally Symmetric Vortex Rings

The motion of vortex rings with bilaterally symmetric initial shape is investigated theoretically and experimentally. The induced velocity at each point on the vortex ring is computed from the Biot‐Savart law. The induced velocity is related to the motion of the ring according to two different concepts: (1) Hydrodynamic vortex—the ring moves with the same velocity as the local fluid; (2) Rankine vortex—the local relative velocity produces lift and drag forces on the ring which serve to distort the ring. Observable vortex rings are produced by pulsing dyed fluid through a rectangular orifice and by staining the starting vortex behind ring wings of various shapes. Good qualitative agreement between the analyses and experiments is achieved.
Local isotropy in complex turbulent boundary layers at high Reynolds number

To continue our (Saddoughi & Veeravalli 1994) tests of the local-isotropy predictions of Kolmogorov's (1941) universal equilibrium theory in shear flows, we have taken hot-wire measurements of the velocity fluctuations in complex turbulent boundary layers at several Reynolds numbers. We have studied the plane-of-symmetry flow upstream of a 4 ft diameter, 6 ft long circular cylinder placed with its axis vertical in the zero-pressure-gradient turbulent boundary layer of the test-section ceiling in the 80 ft x 120 ft Full-Scale Aerodynamics Facility at NASA Ames Research Center.
Optimized Design of Low-Noise Amplifier Based on Behavior-Level Parameter Modeling

This paper proposes an automated optimization method for low-noise amplifiers (LNAs) based on behavioral-level parameters modeling and multi-objective optimization algorithms. Firstly, transistor parameter extraction technique is used to obtain behavioral-level parameters and noise correlation factors, which are then compiled into a lookup table. Secondly, a fast non-dominated sorting genetic algorithm with an elitist preservation strategy (NSGA-II) is used as the LNA multi-objective optimization technique to obtain the values of transistor behavioral-level parameters and matching network component that meet the performance constraints. Finally, transistor size can be obtained through the lookup table. Taking the cascode LNA design as an example, the optimization results prove the effectiveness of NSGA-II based on behavioral-level parameters modeling in LNA design and optimization, which improves the efficiency of LNA optimization design.
An electric arc in a transverse magnetic field: a theory for low power gradient

A uniform electric arc column is held at rest against an imposed low-speed flow perpendicular to its length by an applied magnetic field transverse to both the arc and the flow. The situation is represented mathematically by two regions separated by an isothermal boundary, the arc periphery, across which certain gas properties change discontinuously. It is assumed that the arc has low power gradient so that the Nusselt number is small compared with unity. The Reynolds number is then small also and the methods of the theory of flow at low Reynolds number are used to obtain solutions for the temperature, magnetic field, velocity and pressure inside and outside the arc. It is found that the periphery of the arc is a circle and its radius is determined by heat transfer. The flow near the periphery, and the drag of the arc, are found to depend on a final boundary condition at the periphery, the form of which is not yet clear. Several examples of possible flow patterns are given, and it is shown that the arc may be likened to a slippery porous body for which the slipperiness and porousness are governed by the final boundary condition. The electric and magnetic characteristics of the arc are derived and shown to be amenable to examination by experiment and to empirical extension for arcs of higher power gradient.
THERMAL SHOCK FRACTURE IN AN EDGE-CRACKED PLATE

Abstract In this paper the transient thermal stress problem for an elastic strip with an edge crack is investigated. The elastic medium is assumed to be insulated on one face and cooled by surface convection on the face contaning the edge crack. Using the principle of superposition, the formulation results in a mixed boundary value problem, with the thermal stresses calculated from the thermoelasticity solution for an uncracked strip utilized as the necessary crack surface tractions. The resulting singular integral equation is of a well-known type and is solved numerically. In this paper, inertia effects are assumed negligible and possible temperature dependence of thermoelastic constants is not considered. The numerical results presented, include the stress intensity factor as a function of nondimensional time (Fourier number) and crack length, for various values of the dimensionless Biot number. The temperature distribution and the thermal stresses in the uncracked strip are also included. The time lag,.
Information structure constraints on object marking in Manyika

Abstract Object markers in Bantu languages have commonly been analysed as either agreement morphemes or incorporated pronouns. This paper documents a number of empirical facts concerning object marking in Manyika (chiShona), showing that the distribution of object marking does not fit the predictions of either the agreement or pronominalisation accounts. Specifically, we show that doubling of the object marker and the noun phrase object is in principle possible, but is constrained in a number of instances by the information structure status of the object. This paper therefore makes two distinct claims: first, Manyika object markers (and perhaps other object markers in Bantu languages) ought to be analysed under the rubric of clitics, rather than as agreement morphemes or incorporated pronouns. Second, we claim that the constraints on clitic-doubling are not dependably syntactic in nature; instead, co-occurrence of an object marker and an object is licensed (or not) based on whether the object is in a non-focus domain.
Small Faraday rotation measurement with a Fabry–Pérot cavity

The dependence of the eigenstates of a high‐finesse Fabry–Perot cavity on intracavity circular phase anisotropies is shown to provide a very sensitive method to measure small Faraday rotations. The method is experimentally checked by measuring the Verdet constant of the air and a sensitivity of 10−10 rad is reported.
Modeling the Spatial Distribution of Star Formation in Interacting Disk Galaxies

Models of star-forming interacting galaxies are combined with observational data to investigate the nature of star formation in interacting and merging disk galaxies. Detailed models of specific interacting systems are created using the observed morphology and kinematics of the system to constrain model parameters describing the interaction. The models employ an N-body code to calculate the gravitational dynamics, a discrete cloud model to govern the ISM dynamics, and a modified Schmidt law to describe star formation
Radio observations of the Crab-like supernova remnant 3C 58. I. Total intensity observations

The Crab-like supernova remnant 3C 58 was observed with the VLA at frequencies of 1446 and 4886 MHz, with resolutions of 2.0 and 2.45 arcsec, respectively. It is found that 3C 58 has a considerably larger extent than previously realized, particularly at the eastern and western edges and above and below the central bulge. Some parts of the periphery are markedly confined while others are not; some confined-edge regions are slightly limb brightened. The fainter outer envelope contains extensive filamentation as do the brighter central regions. The filament profiles are nearly identical at 1446 and 4886 MHz. 33 references.
A discrete method for the logarithmic-kernel integral equation on an open arc

Abstract Here we discuss the stability and convergence of a quadrature method for Symm's integral equation on an open smooth arc. The method is an adaptation of an approach considered by Sloan and Burn for closed curves. Before applying the quadrature scheme, we use a cosine substitution to remove the endpoint singularity of the solution. The family of methods includes schemes with any order O(hp) of convergence.
Implicit finite-difference simulations of seismic wave propagation

We propose a new finite-difference modeling method, implicit both in space and in time, for the scalar wave equation. We use a three-level implicit splitting time integration method for the temporal derivative and implicit finite-difference operators of arbitrary order for the spatial derivatives. Both the implicit splitting time integration method and the implicit spatial finite-difference operators require solving systems of linear equations. We show that it is possible to merge these two sets of linear systems, one from implicit temporal discretizations and the other from implicit spatial discretizations, to reduce the amount of computations to develop a highly efficient and accurate seismic modeling algorithm. We give the complete derivations of the implicit splitting time integration method and the implicit spatial finite-difference operators, and present the resulting discretized formulas for the scalar wave equation. We conduct a thorough numerical analysis on grid dispersions of this new implicit .
The organized motion outside a turbulent wake

Velocity fluctuations are measured in both the intermittent and irrotational regions outside the turbulent/nonturbulent interface of a self‐preserving wake. In the outer part of the intermittent region, there is a tendency for all the predictions of the theory of Phillips [Proc. Cambridge Philos. Soc. 51, 220 (1955)] to be satisfied by the nonturbulent data. At larger distances from the interface, the level of the velocity fluctuations becomes comparable with the background turbulence but the organized motion induced by coherent structures within the wake can still be identified. The contribution of this motion to the normal stresses satisfies irrotationality and homogeneity and the amplitude of this motion decays in a manner consistent with Phillips’ theory.
Incipient plasticity of twin and stable/unstable grain boundaries during nanoindentation in copper

An incipient plastic deformation of several types of grain boundaries subjected to nanoindentation was investigated by atomistic simulations. Our previous study showed that the dislocation nucleation in the inner region of the defect-free metals occurs when the resolved shear stress exceeds a particular stress level slightly higher than the ideal shear strength. However, crystal defects such as grain boundaries undermine the nucleation resistance. In this paper, we examined the dislocation nucleation mechanism at the twin and several coincidence site lattice grain boundaries and the resulting weakening of the dislocation nucleation resistance. We found that for the twin and the relatively stable $\ensuremath{\Sigma}11(\overline{1}13)[110]$ grain boundary, the primary slip deformation is activated on the grain-boundary plane prior to the defect-free region because of the low fault energy of the grain boundaries during slip deformation. Subsequently, the secondary slip is activated from the grain boundary. On the other hand, the dislocation is initially generated from the heterogeneous grain-boundary plane for the unstable high-energy grain boundaries.
On Homeomorphisms with Pseudo-Orbit Tracing Property

$x\in X$ if $ d(f^{l}(x), x_{i})<\epsilon$ holds for $i\in(a, b)$ . We say that (X, f) has the pseudo-orbit tracing property (abbrev. P.0.T.P.) if for every $\epsilon>0$ there is $\delta>0$ such that every $\deltap.0$ . of $f$ can be e-traced by some point $x\in X$. Given $x,$ $y\in X$ and $\alpha>0,$ $x$ is $\alpha$-related to $y$ (written $x\alpha\sim y$) if there are $\alpha$-pseudo-orbits of $f$ such that $x_{0}=x,$ $x_{1},$ $\cdots,$ $x_{k}=y$ and $y_{0}=y,$ $y_{1},$ $\cdots,$ $y_{l}=x$ . If $ x\sim y\alpha$ for every $\alpha>0$ , then $x$ is related to $y$ (written $x\sim y$). The chain recurrent set of $f,$ $R$ is $\{x\in X:x\sim x\}$ . ‘ Recall that $\Omega=\{x\in X$: for every neighborhood $U$ of $x,$ $ f^{n}(U)\cap U\neq\emptyset$ for some $n\geqq 1$ }. Clearly $\Omega\subset R$ and both sets are $f$-invariant and closed (a set $E$ will be called $f$-invariant when $f(E)=E$). Assume that (X, f) has the P.0. T.P., then $\Omega=R$ . For, if $x\in R$ then for every $\alpha>0$ there is $\alpha’>0$ with property of the P.0. T.P.; i.e., for every $\alpha^{\prime}p.0$ . $\{x_{i}\}$ such that $x_{0}=x,$ $x_{1},$ $\cdots,$ $x_{k}=x$ , there is $y\in X$ with $d(f^{i}(y), x_{i})<\alpha(0\leqq i\leqq k)$ . Hence $ U_{\alpha}(x)\cap f^{-k}(U_{\alpha}(x))\neq\emptyset$ where $U_{\alpha}(x)=\{y\in X:d(x, y)<\alpha\}$ , and so $ x\in\Omega$ . We proceed with a sequence of lemmas leading to the proof of Theorem 1. For the following (L. 1), (L. 2) and (L. 3), it is assumed that (X, f) has the P.0. T.P. Denote by per $(f)$ the set of all periodic points of $f$.
Ultraluminous IRAS galaxies: Formation of elliptical galaxies by merger-induced dissipative collapse

Evidence that ultraluminous IRAS galaxies are elliptical galaxies forming by merger-induced dissipative collapse are summarized. Tidal tails and shells show that they are recent merger remnants. Near the center, the mass in gas is comparable to the mass in stars within the same radius; since no progenitors are this gas-rich, gas must have collapsed toward the center. Typical central gas densities ∼10 2 M ⊙ pc -3 are as high as stellar mass densities in ellipticals; this solves the well-known problem of producing the observed high densities
The performance of multivariate CUSUM control charts with estimated parameters

In this paper, we study the effect of estimating the vector of means and the variance–covariance matrix on the performance of two of the most widely used multivariate cumulative sum (CUSUM) control charts, the MCUSUM chart proposed by Crosier [Multivariate generalizations of cumulative sum quality-control schemes, Technometrics 30 (1988), pp. 291–303] and the MC1 chart proposed by Pignatiello and Runger [Comparisons of multivariate CUSUM charts, J. Qual. Technol. 22 (1990), pp. 173–186]. Using simulation, we investigate and compare the in-control and out-of-control performances of the competing charts in terms of the average run length measure. The in-control and out-of-control performances of the competing charts deteriorate significantly if the estimated parameters are used with control limits intended for known parameters, especially when only a few Phase I samples are used to estimate the parameters. We recommend the use of the MC1 chart over that of the MCUSUM chart if the parameters are estimated from a small number of Phase I samples.