Miracle-dz/UniFAR-FTUs huggingface dataset:
On the nature of the polarization opposition effect exhibited by Saturn's rings

The nature of the unusually narrow photometric and polarization opposition effects exhibited by Saturn's A and B rings is examined using a theory and results of laboratory measurements. It is pointed out that the small angular width of both phenomena makes it difficult to explain them on the basis of the commonly used shadowing models. On the other hand, it is known from laboratory experiments and theoretical studies, that a strong and very narrow opposition peak in the reflected intensity can be produced by coherent backscattering of light from powderlike layers of small regolithic grains. Using Ozrin's (1992) rigorous vector theory of coherent backscattering, it is shown that, for subwavelength-sized regolithic particles, the photometric opposition effect is accompanied by a polarization opposition effect of the same angular width. This suggests that the polarization opposition effect of the Saturn's ring has the same origin as the photometric opposition effect and is due to coherent backscattering of light from the regolithic layer composed of the submicrometer-sized ice grains.
All-fiber 1.15-mJ pulsed eye-safe optical source

We report a MOPA (master oscillator - power amplifier) pulsed optical fiber source emitting high-brightness radiation (M2 = 1.65) in the “eye-safe” 1.55 μm region. A high pulse energy of 1.15 mJ was reached at low repetition rates while the maximum average output power was 2.2 W at a wavelength of 1562 nm.
Inelastic processes in collisions of H + ions with C, N, O, and Si atoms below 1 keV

Electron capture in collisions of C, N, O, and Si atoms with H{sup +} ions is studied theoretically based on a molecular representation within a fully quantum framework by including six molecular channels both for the ground and excited states for the [H{sup +}+C] system, and four channels for the ground-state [H{sup +}+N] and [H{sup +}+O] systems. For the [H{sup +}+Si] system, we employed the molecular representation both in fully quantum and semiclassical frameworks to investigate electron capture at higher energy as well. The {ital ab initio} potential curves and nonadiabatic coupling matrix elements for all these systems are obtained from multireference single- and double-excitation configuration interaction calculations. For all systems, the effect of excited atoms on electron capture is examined in addition to that from the ground state. Because of a small asymptotic energy defect (near-resonant processes) between the initial and closest electron capture channels for almost all systems, electron capture cross sections from the ground-state atoms are large with values of approximately 10{sup {minus}16}{minus}10{sup {minus}15}cm{sup 2} for all systems at above 100 eV. Corresponding rate coefficients are found to be much smaller than those previously reported for the NH{sup +} and OH{sup +}, but, on the contrary, foundmore » to be larger by a few orders of magnitude than the previously estimated value for the SiH{sup +} system. Those from excited states are also found to be extremely efficient for all cases. {copyright} {ital 1997} {ital The American Physical Society}« less
Numerical evidence for non-Abelian quantum liquids in the lowest Landau level

Signatures of non-Abelian statistics are sought in correlated liquids of composite fermions CFs responsible for a “second generation” of fractional quantum Hall effect. The hierarchy stems from the zero-energy state of a model CF interaction by means of a flux attachment procedure converting this uniquely correlated state of “first-generation” CFs to a filled shell of second-generation CF ’s. Quasiholes of this state do not obey Abelian statistics. The hierarchy is confirmed numerically, including known states at filling factors e=4 /11 and 3/8 and a hypothetical state at e=9 /25.
Effect of bulk inversion asymmetry on [001], [110], and [111] GaAs/AlAs quantum wells

The spin splitting of the conduction band due to the inversion asymmetry of the microscopic crystal potential is predicted to depend linearly on the components of the parallel wave number ${\mathrm{k}}_{\ensuremath{\parallel}}$ for small ${k}_{\ensuremath{\parallel}}$ in undoped GaAs/AlAs quantum wells. The linear dependence is due to the quantization of the confinement levels; the bulk spin splitting depends cubically on $\mathrm{k}$. We have calculated the splitting both numerically and analytically for GaAs/AlAs quantum wells grown along the [001], [110], and [111] directions. In the linear regime the average spin splitting is shown to be about a factor of 2 smaller for [110] quantum wells than for [001]- and [111]-grown quantum wells. The splitting is calculated to be $\ensuremath{\Delta}E=4$ meV at ${k}_{\ensuremath{\parallel}}=0.07(\frac{2\ensuremath{\pi}}{a})$ for a 25-\AA{} [001]-grown GaAs/AlAs quantum well.
Theoretical analysis of nth-order cascaded continuous-wave Raman fiber lasers. II. Optimization and design rules

Using the analytical model we developed for an nth-order cascaded Raman laser, we find the design rules for such lasers. We determine analytical expressions for the cavity length and the output-coupler reflectivity that maximize the output power and minimize threshold power. Simple expressions are obtained in the depleted-pump approximation. Deviations from these expressions when the pump is not completely depleted are shown to be different depending on the parity of the number n of Stokes shifts (cascades). The design rules show that the mirror reflectivity is a critical factor in the laser quality and that the ultimate slope efficiency epsilon is found to be g_n/g_0. We also find a condition to determine if P-doped fibers are more useful than Ge-doped fibers in Raman fiber lasers based only on the Raman shift and absorption of the fibers.
GRANULATION IN THE PHOTOSPHERE OF ζ CYGNI

A series of 35 high-resolution spectra are used to measure the third-signature plot of the G8 III star, ζ Cygni, which shows convective velocities only 8% larger than the Sun. Bisector mapping yields a flux deficit, a measure of granulation contrast, typical of other giants. The observations also give radial velocities with errors ∼30 m s−1 and allow the orbit to be refined. Velocity excursions relative to the smooth orbital motion, possibly from the granulation, have values exceeding 200 m s−1. Temperature variations were looked for using line-depth ratios, but none were found.
Nonparametric inference in multivariate mixtures

We consider mixture models in which the components of data vectors from any given subpopulation are statistically independent, or independent in blocks. We argue that if, under this condition of independence, we take a nonparametric view of the problem and allow the number of subpopulations to be quite general, the distributions and mixing proportions can often be estimated root-n consistently. Indeed, we show that, if the data are k-variate and there are p subpopulations, then for each p g 2 there is a minimal value of k, k-sub-p say, such that the mixture problem is always nonparametrically identifiable, and all distributions and mixture proportions are nonparametrically identifiable when k g k-sub-p. We treat the case p e 2 in detail, and there we show how to construct explicit distribution, density and mixture-proportion estimators, converging at conventional rates. Other values of p can be addressed using a similar approach, although the methodology becomes rapidly more complex as p increases. Copyright 2005, Oxford University Press.
Approximating zeros of accretive operators

Let A be an m-accretive set in a reflexive Banach space E with a Gateaux differentiable norm. For positive r let Jr denote the resolvent of A. If the duality mapping of E is weakly sequentially continuous and 0 is in the range of A, then for each x in E the strong lim ooj x exists and belongs to A-1(0). This is an extension to a Banach space setting of a result previously known only for Hilbert space. Let H be a real Hilbert space and U C H x H a maximal monotone operator. For each positive r there is a unique y r in H such that 0 e Yr + rU(y). It is known [4] that if 0 belongs to the range of U, then the strong limroo yr exists and is the point of U-1(0) closest to 0. It is our purpose in this note to extend this result to accretive operators in certain Banach spaces. According to [4], this leads to the possibility of calculating a zero of the given operator as the limit of an iteratively constructed sequence. Our method of proof is not a direct generalization of the Hilbert space proof. It works, however, only in a restricted class of Banach spaces. The question of whether our theorem is valid in other Banach spaces remains open. Let E* denote the dual of a real Banach space E. The duality mapping J from E into the family of nonempty subsets of E * is defined by J(x) = lx* c E*: (x, x*) = 11 x12 and ||x*|| = ||x|}. J is single-valued if and only if the norm of E is Gateaux differentiable. If A is a subset of E x E and x e E, we define Ax = ye E: [x, yle Al and set D(A)= IxE E: Ax/0}. The range of A is defined by R(A)= U Ax: x E D( A)} Received by the editors October 1, 1974. AMS (MOS) subject classifications (1970). Primary 47H15, 47H05; Secondary 47B44, 40A05.
Robustness and modeling error characterization

The results on robustness theory presented here are extensions of those given in [1]. The basic innovation in these new results is that they utilize minimal additional information about the structure of the modeling error as well as its magnitude to assess the robustness of feedback systems for which robustness tests based on the magnitude of modeling error alone are inconclusive.
Approximate penalization path for smoothly clipped absolute deviation

Feature selection often constitutes one of the central aspects of many scientific investigations. Among the methodologies for feature selection in penalized regression, the smoothly clipped and absolute deviation seems to be very useful because it satisfies the oracle property. However, its estimation algorithms such as the local quadratic approximation and the concave–convex procedure are not computationally efficient. In this paper, we propose an efficient penalization path algorithm. Through numerical examples on real and simulated data, we illustrate that our path algorithm can be useful for feature selection in regression problems.
Three-dimensional pattern transfer and nanolithography: modified soft molding

One-step transfer of molded three-dimensional polymer structures into underlying substrate is reported. The one-step transfer is made possible by a molding technique presented here in the form of modified soft molding. Formation of a desired three-dimensional structure in a polymer film by this method, followed by one-step reactive ion etching, is utilized for the transfer. The technique is also shown to be effective in transferring sub-100-nm features.
Serendipitous discovery of a redshift 4.4 QSO

The serendipitous discovery of an extremely high-redshifted QSO during long-slit observations of an unrelated object is reported. The QSO spectrum contains strong emission lines of Ly-alpha, NV 1240 A, and C IV 1549 A, as well as weaker Ly-beta, O VI, 1034 A, Si II 1262 A, and semiforbidden Si IV/O IV 1400 A. There is a prominent break in the continuum level blueward of Ly-alpha. The derived redshift is 4.406 + or - 0.005, one of the highest known. 22 references.
Investigating the West African Climate System Using Global/Regional Climate Models

Abstract A three-day workshop took place at Howard University in Washington D.C. 27 July through 29 July 2000 to examine scientific and social issues associated with climate research in West Africa. Atmospheric scientists from West Africa and United States presented research and sought solutions to various problems that exist with respect to the state of science in West Africa. Presentations covered global climate model (GCM) and regional climate model simulations for West Africa, easterly wave representation in GCMs and the NCEP reanalysis, land-surface processes and atmospheric chemistry. A number of obstacles currently inhibit West African-U.S. collaboration including a lack of resources, communications, technology, and language. In order to overcome these obstacles, sustained efforts by numerous individuals in United States and West Africa are necessary. An institute in West Africa should be identified that can serve as a center for education, research, and a base for international field studies in th.
Pre-stack migration applied to GPR for landmine detection

Detection of buried landmines by ground penetrating radar (GPR) normally suffers from very strong clutter that will decrease the image quality in GPR data. Problems are also encountered when imaging steeply dipping landmines by GPR. To solve these problems, we have developed a stepped-frequency continuous-wave array antenna ground penetrating radar system, called SAR-GPR, that can acquire common middle point multi-offset data. As an approximate solution to the general wavefield inversion problem, migration algorithms were used to refocus the scattered landmine information to improve signal–clutter ratio and re-construct the landmine image. Also, pre-stack migration was found to efficiently deal with the steeply dipping landmine problem. Before migration processing, subtracting antenna coupling was used. The SAR-GPR system was tested under two conditions. The first condition is designed to simulate inhomogeneous soil under rough ground conditions and the second condition is to simulate steeply dipping buried landmine. Very strong clutter in the GPR data was exhibited in the first condition. After pre-stack migration, strong clutter was efficiently suppressed and a high quality landmine image was re-constructed in both experiments.
Multiple parameter monitoring in a direct methanol fuel cell

Direct methanol fuel cells (DMFCs) are promising candidates for energy supply based on renewable sources. They provide a high power density and the possibility of an easy recharge. Moreover, the fuel storage is significantly easier than it is for hydrogen fuel cells. However, in continuous operation, supplying the anode with a constant concentration of methanol is the key to achieving stable and optimal performance. Hence, developing a method for measuring the methanol content of the fuel online is desirable for advanced monitoring of the fuel cell. In this work, we report the combined application of Raman spectroscopy, chronoamperometry and gravimetry for the simultaneous determination of the methanol concentration and the Faradaic efficiency in a DMFC. Raman spectroscopy is used to measure the actual methanol concentration supplied to the anode. The chronoamperometric and gravimetric measurements allow the theoretical methanol concentration, i.e. assuming that methanol is only consumed by electro-oxidation, to be determined. The full set of data ultimately facilitates the calculation of the Faradaic efficiency.
Effects of hearing differences on encoding and comparison information‐processing stages

Reaction times to spoken digits presented in a speeded memory scanning procedure were measured for groups of listeners with normal hearing (N=24) and with congenital or early‐onset sensorineural hearing losses (N=12). Separate groups of 12 normal‐hearing listeners were tested under conditions of good stimulus quality (no distortion, high SNR) versus poor stimulus quality (low‐pass filtered, low SNR). The speeded memory scanning procedure allows total reaction time to be decomposed into ‘‘encoding’’ and ‘‘comparison’’ components which correspond to separate stages in a model of human information processing. At issue here is whether long‐term effects of hearing loss, such as possible deficits in phonological and/or lexical representation of spoken language, lead to unusual processing costs at either the encoding or comparison stage. Experimental results suggest that impaired listeners incur the same encoding costs as normal‐hearing listeners presented with poor‐quality stimuli. However, comparison costs for.
Short-range magnetic collapse of Fe under high pressure at high temperatures observed using x-ray emission spectroscopy

Understanding the high-pressure electronic properties of Fe still poses both theoretical and experimental challenges. Here, we evidence the short-range magnetic collapse of Fe in the $\ensuremath{\gamma}$ phase by x-ray emission spectroscopy carried out in situ under high-pressure and high-temperature conditions, up to 20 GPa and 1400 K. We find an abrupt decrease in the Fe spin state in $\ensuremath{\gamma}\text{-Fe}$ at high pressure similar in amplitude to the known $\ensuremath{\alpha}\text{\ensuremath{-}}\ensuremath{\epsilon}$ magnetic collapse transition. A careful analysis of the Fe spin state in the $\ensuremath{\epsilon}$ phase indicates a sluggish diminution right above the transition pressure, bearing out recent predictions of residual, likely noncollinear, magnetism in this phase. In the $\ensuremath{\gamma}$ phase, our results demonstrate that the dominant mechanism at high pressure is a high-spin to low-spin transition. Implications for the elastic properties of Fe at extreme conditions are analyzed.
FITTING FINITE MIXTURE MODELS IN A REGRESSION CONTEXT

Suppose data are collected in a three-mode fashion (individuals x items X attributes), and it is sought to cluster the individuals into groups on the basis of lineat relations between scores on the attributes for each item and auxiliary measurements made on the same items. A mixture model is pro posed and the EM algorithm is used to fit it to the data by simultaneously estimating the group parameters and allocating individuals to groups. The method is illustrated by a simulation study and a real example in which consumers are clustered on the basis of product scores that are related to a sensory laboratory measurement.
Locality Preserving Maximum Scatter Difference Projection for Face Recognition

Maximum Scatter Difference (MSD) aims to preserve discriminant information of sample space, but it fails to find the essential structure of the samples with nonlinear distribution. To overcome this problem, an efficient feature extraction method named as Locality Preserving Maximum Scatter Difference (LPMSD) projection is proposed in this paper. The new algorithm is developed based on locality preserved embedding and MSD criterion. Thus, the proposed LPMSD not only preserves discriminant information of sample space but also captures the intrinsic submanifold of sample space. Experimental results on ORL, Yale and CAS-PEAL face database indicate that the LPMSD method outperforms the MSD, MMSD and LDA methods under various experimental conditions.
Broad-band microstrip antennas using additional resonators gap-coupled to the radiating edges

A method for increasing the bandwidth of microstrip patch antennas by incorporating two additional resonators which are gap-coupled to the radiating edges of a rectangular patch is described. A two-dimensional analysis using Green's function and segmentation method is used for analyzing the proposed antenna configurations. A bandwidth as large as five times a single rectangular patch is obtained in S -band. Changes in the radiation pattern over this wide bandwidth are discussed. Experimental results are in reasonable agreement with the analysis.
Improvement of performances in time-domain breast DOT by the aid of image segmentation

The investigations on the optical mammography have attracted many clinical attentions, since the conventional X-ray mammography has shown some deficiencies in sensitivity, specificity, security and comfortableness. In this study, we propose an image reconstruction technique of time-domain diffuse optical tomography (DOT) for the optical mammography in the first place. This technique uses the finite-element method (FEM) solution to the Laplace-transformed coupled diffusion equations as the forward model, and develops an inverse model based on a Newton-Raphson scheme. On the basis of the preliminary reconstructed image of this technique, we also present an efficient Jacobian reduction method by the aid of image segmentation to obtain a more accurate image reconstruction. The simulative experiments reveal that the performance of reconstructed image by the aid of the image segmentation makes a notable improvement on the conventional algorithm in breast phantom image.
Iterative Frequency Domain Equalization for Single-Carrier Space Time Diversity Systems

Single carrier frequency domain equalization (SC-FDE) has been receiving much attention for its advantage of suppressing inter-symbol interference (ISI). We proposed a frequency domain iterative decision feedback equalization (FD-IDFE) algorithm for single carrier space time block coding (STBC) systems. The paper use the multi-antenna transmit and Alamouti signaling scheme to achieve the significant diversity gain. We design the feedback equalization structure by Mean Square Error (MSE) criterion and Lagrange optimization method, and we also consider the parameters estimation. At last, we compare the proposed algorithm with the conventional equalization schemes, the simulation results illustrate that our method has excellent performance.
Enhanced performance of white polymer light-emitting diodes using polymer blends as hole-transporting layers

AU: PLEASE CONFIRM CHANGES MADE IN THE BYLINE.White polymer light-emitting diodes (WPLEDs) with the Commission Internationale de l’Enclairage coordinates of (0.32, 0.34) are demonstrated with poly(9,9-dioctylfluorene-2,7-diyl) as host and poly(5-methoxy-2-(2′-ethyl-hexylthio)-p-phenylenevinylene) as guest. Blends of poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] (poly-TPD) and poly(N-vinyl-carbazole) (PVK) are introduced into bilayer devices as hole-transporting layers (HTLs). Because the blends combined the hole-injection and hole-transporting capabilities of poly-TPD with electron-blocking capability of PVK, WPLEDs with the blends as HTLs exhibit enhanced performance in comparison with single-layer device and bilayer devices with pure poly-TPD or pure PVK as HTL. With a 1:1 weight ratio of poly-TPD to PVK in the blend, the WPLED achieves a maximum brightness of ∼5000cd∕m2 with a maximum electroluminescent efficiency of 3.15cd∕A.
Zeeman measurements of the magnetic fields at the Galactic center

There is mounting evidence that suggests magnetic fields are important in a range of phenomena observed in the Galactic center. We report here Zeeman measurements of the magnetic field in the dense molecular gas in the circumnuclear disk (CND; inner radius ∼1.7 pc) using the 1667 MHz OH absorption against the continuum radio source at the Galactic center (Sgr A). These observations with a resolution of 3″×4″ (∼0.15 pc at 8 kpc) were made with the Very Large Array
Methodology Review: Nonparametric IRT Approaches to the Analysis of Dichotomous Item Scores

This paper reviews developments in nonparametric item response theory (NIRT). Historically, Mokken's (1971) item response theory (IRT) model and procedure of scale analysis have been the starting point for NIRT models; the developments that Mokken's work have inspired and those that originated independently are discussed here. Attention is focused on results pertaining to dichotomously scored items. The usefulness of new theoretical results for practical test construction is explained. NIRT is especially useful when the purpose of test application is to order persons, items, or both. The assumptions inherent in several NIRT models, model-data fit methods, item selection procedures, and reliability methods are discussed. NIRT models often allow more items into a test than stronger models, yielding higher reliability and better coverage of the latent trait. Moreover, the theoretical results from NIRT are often relevant to parametric IRT. Examples include conditional association and manifest monotonicity, as well as recent results for polytomous NIRT models that concem the ordering of persons, which also hold for several parametric IRT models.