Miracle-dz/UniFAR-FTUs huggingface dataset:
Limits on quark-lepton compositeness scales from dileptons produced in 1.8 TeV pp-collisions

The dilepton mass spectrum in p{bar p}{r_arrow}l{sup +}l{sup {minus}}+X interactions is studied using dielectrons ({ital ee}) and dimuons ({mu}{mu}) in 110 pb{sup {minus}1} of data collected with the Collider Detector at Fermilab. The data are consistent with standard model predictions. The mass spectrum, being a probe for new physics, is examined for new interactions of quarks and leptons from a common composite structure. Assuming a contact interaction with the conventional coupling g{sup 2}{sub 0}/4{pi}=1 , limits on chiral quark-electron and quark-muon compositeness scales in the range of 2.5 to 4.2TeV are obtained. {copyright} {ital 1997} {ital The American Physical Society}
Dielectronic satellite spectra of hydrogenlike titanium (Ti xxii)

High resolution spectra of the Ly . cap alpha. /sub 1/ and Ly . cap alpha. /sub 2/ lines of hydrogenlike titanium, TiXXII, and the associated dielectronic satellites which are due to transitions 1snl-2pnl with n greater than or equal to 2, have been observed from tokamak discharges with auxiliary ion cyclotron heating (ICRH) with central electron temperatures of 2 keV and central electron densities of 8 x 10/sup 13/ cm/sup -3/ on the Princeton Large Torus (PLT). The data have been used for a detailed comparison with theoretical predictions based on the Z - expansion method and Hartree - Fock calculations. The results obtained with the Z - expansion method are in excellent agreement with the observed spectral data except for minor discrepancies between the theoretical and experimental wavelengths of 0.0003 A for the n = 2 satellites and of 0.0001 A for the separation of the Ly . cap alpha. /sub 1/ and Ly . cap alpha. /sub 2/ lines. Very good agreement with the experimental data is also obtained for the results from the Hartree - Fock calculations though somewhat larger discrepancies (approx. = 0.0009 A) exist between experimental and theoretical wavelengths which are systematically too small. The observed spectra are used for diagnosis ofmore » the central ion and electron temperatures of the PLT discharges and for a measurement of the dielectronic recombination rate coefficient of TiXXII. « less
A 3-channel CCD photometer at the Xinglong Observatory

We describe the design and construction of a new rapid 3-channel CCD photometer, dedicated to simultaneous multicolor photometric observations of rapidly variable objects. This photometer is equipped on the 1-meter telescope at the Xinglong Observatory. It allows simultaneous imaging within fields of view of 18.8′ × 18.8′, 18.2′ × 17.6′ and 9.2′ × 9.2′ in the Sloan Digital Sky Survey's g′, r′ and i′ bands, respectively. The results of its calibration and performance are reported.
Heating induced microstructural changes in graphene/Cu nanocomposites

Dynamic heating experiments on graphene/Cu nanocomposites by in situ scanning electron microscopy were conducted to observe the evolution of the morphology and size of the Cu nanoparticles. Microstructural characterization showed that the graphene/Cu nanocomposites system consists of graphene sheets decorated with Cu-based nanoparticles with different chemistries (Cu, Cu2O), shapes (cube, rod, triangle, etc) and sizes. Evidence of neck evolution, coalescence, sublimation and Ostwald ripening were observed. Interestingly, some of the events occurred at the edges of the graphene sheets. The quantitative data of necking evolution deviates from the classical continuum theory indicating that intrinsic faceting and the shape of the nanoparticles played an important role in the necking process. This was supported by molecular dynamics simulations. Experimental data of liquid-spherical nanoparticles on graphene suggested that Cu did not wet graphene. Based on sublimation experiments and surface stability, we propose that graphene decorated with Cu nanoparticles enclosed by {1 1 1} facets are the most stable nanocomposite at high temperatures. The growth mechanism of nanoparticles on graphene is discussed.
The long-time behavior of finite-element approximations of solutions of semilinear parabolic problems

Error estimates for finite-element approximations of the solutions to semilinear parabolic problems are proved. Under the hypothesis that the exact solution is asymptotically stable as $t \to \infty $, error estimates of optimal order that hold uniformly on the unbounded time interval $0 \leqq t < \infty $ are obtained. Both semidiscrete and completely discrete approximations are considered.
Tidal Effects on Spherical Stellar Systems

Many self-gravitating stellar systems are satellites of larger galaxies and must there­ fore be subjected to the tidal field of the parent system. Examples are the globular clusters and dwarf elliptical galaxies, which are satellites of our Galaxy. Most previous studies of tidal effects have been highly simplified, e.g. clusters in circular planar galactic orbits (Bok, 1934), or have assumed that the tidal field acts to limit the size of a star cluster without any effects on its internal structure or stability (Spitzer and Shapiro, 1972; Spitzer and Thuan, 1972). To determine the effects of a realistic time varying tidal field on a stellar system where binary encounter processes are unimportant, we computed the orbits of a large and representative sample of test particles in the field of a spherically symmetric smooth model of a star cluster which, in turn, moved in its own orbit around a model galaxy. The effect of the tidal fields on the stellar orbits was investigated by observing the evolution of the stars in energy E and angular momentum h. E and h are, of course, conserved quantities for an isolated spherically symmetric field. Three systems were tested. Two involved a point mass galaxy with the cluster in an elliptical orbit about it. The third system used a rotationally symmetric model of a disk halo galaxy. The mass model was constructed to fit the mass distribution and kinematics of our Galaxy (Innanen, 1973). This system was an analogue for a 'typical' halo globular cluster in our Galaxy. The three body equations of motion were integrated using an IBM 370/75 system and a fast double precision algorithm kindly supplied by Dr F. T. Krogh of J. P. L. (Krogh, 1969, 1971). The main conclusion reached in these numerical experiments is that star clusters rotating in a retrograde sense compared with their galactic orbital motion, are much more stable in a tidal field than clusters with either direct rotation or no rotation. Observational support is given to this by measurement of the rotation of co Centauri (Harding, 1965; Keenan et a/., 1973) and of M13 (Griffin, 1972a, b, 1974). The most stable stellar orbits are low-eccentricity, low inclination retrograde orbits. The least stable are similar direct orbits. For the case of a disk model galaxy, the stellar orbits inclined at large angles to the galactic plane are also highly perturbed due to the large field gradients across the disk in the vertical direction. The galactic orbits of the stars which escaped from the model cluster due to the tidal interaction were also computed The escapers were grouped into two 'clumps' in energy-angular momentum phase space. These clumps are separated from each other and from the point occupied by the parent cluster in orbital energy and angular momentum phase space. One 'clump' has lower energy and angular momentum than the cluster while the other has higher.
Impedance matching by the combined effects of the outer and middle ear

When the impedance mismatch between air and the oval window is computed by considering the latter as a small piston in a baffle, and taking the appropriate source impedance into account, it can be shown that the mismatch is frequency dependent and may be greater than 50 dB at 100 Hz. The middle ear transformer by itself is inadequate to compensate for the loss of transmission due to the mismatch. Only at the frequency of the outer ear resonance does the combined action of the outer ear and the middle ear produce an estimated gain that roughly compensates for the loss of energy at the interface. Detailed computations are shown for cats, and some results applicable to the human ear are also included.
On the gradient flow for the anisotropic area functional

We consider the anisotropic mean curvature flow for parametrized hypersurfaces and provide a new definition of gradient flow that takes into account the anisotropic nature of space. With this new approach we succeed in identifying the natural candidate for the anisotropic mean curvature vector using a variational method. Under the obtained flow Wulff shapes shrink self similarly. The new definition of gradient flow relies on understanding which Banach structure plays a fundamental role and performing a consistent choice of function spaces. The geometric setting we introduce also allows us to provide and justify a natural formulation for the anisotropic Willmore functional. Its first variation is computed.
Numerical simulation: Toward the design of high-efficiency planar perovskite solar cells

Organo-metal halide perovskite solar cells based on planar architecture have been reported to achieve remarkably high power conversion efficiency (PCE, >16%), rendering them highly competitive to the conventional silicon based solar cells. A thorough understanding of the role of each component in solar cells and their effects as a whole is still required for further improvement in PCE. In this work, the planar heterojunction-based perovskite solar cells were simulated with the program AMPS (analysis of microelectronic and photonic structures)-1D. Simulation results revealed a great dependence of PCE on the thickness and defect density of the perovskite layer. Meanwhile, parameters including the work function of the back contact as well as the hole mobility and acceptor density in hole transport materials were identified to significantly influence the performance of the device. Strikingly, an efficiency over 20% was obtained under the moderate simulation conditions.
Heusler compounds as ternary intermetallic nanoparticles: Co2FeGa

This work describes the preparation of ternary nanoparticles based on the Heusler compound Co2FeGa. Nanoparticles with sizes of about 20 nm were synthesized by reducing a methanol impregnated mixture of CoCl2 · 6H2O, Fe(NO3)3 · 9H2O and Ga(NO3)3 · xH2O after loading on fumed silica. The dried samples were heated under pure H2 gas at 900 °C. The obtained nanoparticles—embedded in silica—were investigated by means of x-ray diffraction (XRD), transmission electron microscopy, temperature dependent magnetometry and Mößbauer spectroscopy. All methods clearly revealed the Heusler-type L21 structure of the nanoparticles. In particular, anomalous XRD data demonstrate the correct composition in addition to the occurrence of the L21 structure. The magnetic moment of the particles is about 5μB at low temperature in good agreement with the value of bulk material. This suggests that the half-metallic properties are conserved even in particles on the 10 nm scale.
Potential benefit of the CT adaptive statistical iterative reconstruction method for pediatric cardiac diagnosis

Adaptive Statistical Iterative Reconstruction (ASIR) is a new imaging reconstruction technique recently introduced by General Electric (GE). This technique, when combined with a conventional filtered back-projection (FBP) approach, is able to improve the image noise reduction. To quantify the benefits provided on the image quality and the dose reduction by the ASIR method with respect to the pure FBP one, the standard deviation (SD), the modulation transfer function (MTF), the noise power spectrum (NPS), the image uniformity and the noise homogeneity were examined. Measurements were performed on a control quality phantom when varying the CT dose index (CTDIvol) and the reconstruction kernels. A 64-MDCT was employed and raw data were reconstructed with different percentages of ASIR on a CT console dedicated for ASIR reconstruction. Three radiologists also assessed a cardiac pediatric exam reconstructed with different ASIR percentages using the visual grading analysis (VGA) method. For the standard, soft and bone reconstruction kernels, the SD is reduced when the ASIR percentage increases up to 100% with a higher benefit for low CTDIvol. MTF medium frequencies were slightly enhanced and modifications of the NPS shape curve were observed. However for the pediatric cardiac CT exam, VGA scores indicate an upper limit of the ASIR benefit. 40% of ASIR was observed as the best trade-off between noise reduction and clinical realism of organ images. Using phantom results, 40% of ASIR corresponded to an estimated dose reduction of 30% under pediatric cardiac protocol conditions. In spite of this discrepancy between phantom and clinical results, the ASIR method is as an important option when considering the reduction of radiation dose, especially for pediatric patients.
Geometry of the Algebraic Riccati Equation, Part I

We synthesize and generalize the two principal methods for classifying the set of real symmetric solutions of the algebraic Riccati equation (ARE) to obtain a result which combines the advantages of both existing methods. The geometric approach we take also clarifies the roles of controllability and observability in the theory of the ARE. In addition, we discuss the properties of a special subset of the solution set of the ARE, the unmixed solutions, and find that they exhibit many of the same properties as the extremal solutions, $K^ + $ and $K^ - $.
Order and Disorder in Ferroelectrics

Recent developments in the understanding of order-disorder and displacive type transitions are presented. It is shown that classical order-disorder type transitions like those in squaric acid and KDP contain in addition to the order disorder also a displacive component in the phase transition mechanism. Similarly classical displacive ferroelectrics like BaTiO3 which have been traditionally described by the condensation of the soft mode contain an order-disorder component as the Ti ion is dynamically disordered between different off-center sites already in the cubic phase. The comparison of the experimental and theoretical electric field gradient tensors at the Ti sites in the various phases of BaTiO3 allows for a quantitative determination of the mixed character of this phase transition.
Study on Fuzzy PID Control of Amplitude Modulation Atomic Force Microscopy

According to the characteristics of probe motion of Amplitude Modulation Atomic Force Microscopy (AM-AFM), the model of AM-AFM probe dynamic process is obtained through Euler - Bernoulli's equation. Based on AM-AFMs negative feedback control system with a fuzzy PID control module, a complete AM-AFM system simulation platform is established. By using fuzzy system, fuzzy PID controller makes the real-time adjustment of PID parameters come true, that is, this method overcomes the difficulties of traditional PID parameter tuning and thus high-quality control effect is achieved. Moreover, this article got a set of initial value of off-line adjustment using Ziegler-Nichols method. The value is applied in the setting of fuzzy center so as to further improve the control effect. The simulation of the scanning of two typical samples is made to demonstrate the control effect of fuzzy PID. It proves the control effect of fuzzy PID and indicates that fuzzy PID can significantly improve the AM-AFM image quality of samples which have steep surface.
Scaling in the shock–bubble interaction

The passage of a shock wave through a spherical bubble results in the formation of a vortex ring. In the present study, simple dimensional analysis is used to show that the circulation is linearly dependent on the surrounding material speed of sound c, and the initial bubble radius R. In addition, it is shown that the velocities characterizing the flow field are linearly dependent on the speed of sound, and are independent of the initial bubble radius. The dependence of the circulation on the shock wave Mach number M is derived by Samtaney and Zabusky (1994) as (1 + 1/M + 2/M 2 ) (M - 1). Experiments were performed for slow/fast (air-helium) and fast/slow (air-SF 6 ) interactions. Full numerical simulations were conducted resulting in good agreement. From the results, it is seen that in both cases, according to the proposed scaling, the vortex ring velocity is bubble radius independent. The numerical results for the slow/fast interaction show that the proposed Mach scaling is valid for M < 2. Above M ≅ 2, the topology of the bubble changes due to a competition between the upstream surface of the bubble and the undisturbed shock wave.
Identifiable Surfaces in Constrained Optimization

The concept of a “class-$C^p $ identifiable surface” of a convex set in Euclidean space is introduced. The paper shows how the smoothness of these surfaces is related to the smoothness of the projection operator and presents finite identification results for certain algorithms for minimization of a function over this set. The work uses a partially geometric view of constrained optimization to generalize previous finite identification results.
Microphysical Modeling of Ground-Level Aircraft-Emitted Aerosol Formation: Roles of Sulfur-Containing Species

Particulate matter emissions from aircraft engines have received increased attention due to their impacts on climate, health, and regional air quality. However, understanding of particulate matter formation from aircraft emissions at ground level is still limited. In this work, a detailed, one-dimensional model consisting of plume chemistry, wake dilution, and aerosol microphysics was developed to study sulfur-containing aerosol formation in near-field aircraft plumes at ground level. Parametric studies of ambient conditions and engine operating parameters were performed following the centerline plume trajectories up to 1 km downstream. The sampling system used in a recent experimental measurement campaign (NASA APEX-1) was also investigated. Our results show that binary homogeneous nucleation of H 2 SO 4 -H 2 O is sensitive to ambient conditions, and heterogeneous condensation on soot is dependent on engine power. The results also suggest that at certain atmospheric conditions the observations from the experimental sampling system at moderate (e.g., 30 m) downstream locations may not represent the particle evolution further downstream. A comparison with experimental data provided a limited initial assessment of the model. This assessment suggests that the important physics are being captured, and the model may be used to interpret experimental results and help guide future directions of field measurements.
Closed Form Pricing of European Options for a Family of Normal-Inverse Gaussian Processes

In this article, the author assumes that the stock price dynamics follows the exponential of the normal-inverse Gaussian process. Analytical formulas for values of digital options and European calls are obtained. The considered family of the four-parametric normal-inverse Gaussian processes has steepness parameter . The established formulas depend on the values of the degenerate Appell hypergeometric function.
To fit or not to fit: evaluating stable isotope mixing models using simulated mixing polygons

Stable isotope analysis is often used to identify the relative contributions of various food resources to a consumer's diet. Some Bayesian isotopic mixing models now incorporate uncertainty in the isotopic signatures of consumers, sources and trophic enrichment factors (e.g. SIAR, MixSIR). This had made model outputs more comprehensive, but at the expense of simple model evaluation, and there is no quantitative method for determining whether a proposed mixing model is likely to explain the isotopic signatures of all consumers, before the model is run. Earlier linear mixing models (e.g. IsoSource) are easier to evaluate, such that if a consumer's isotopic signature is outside the mixing polygon bounding the proposed dietary sources, then mass balance cannot be established and there is no logical solution. This can be used to identify consumers for exclusion or to reject a model outright. This point‐in‐polygon assumption is not inherent in the Bayesian mixing models, because the source data are distributions not average values, and these models will quantify source contributions even when the solution is very unlikely. We use a Monte Carlo simulation of mixing polygons to apply the point‐in‐polygon assumption to these models. Convex hulls (‘mixing polygons’) are iterated using the distributions of the proposed dietary sources and trophic enrichment factors, and the proportion of polygons that have a solution (i.e. that satisfy point‐in‐polygon) is calculated. This proportion can be interpreted as the frequentist probability that the proposed mixing model can calculate source contributions to explain a consumer's isotopic signature. The mixing polygon simulation is visualised with a mixing region, which is calculated by testing a grid of values for point‐in‐polygon. The simulation method enables users to quantitatively explore assumptions of stable isotope analysis in mixing models incorporating uncertainty, for both two‐ and three‐isotope systems. It provides a quantitative basis for model rejection, for consumer exclusion (those outside the 95% mixing region) and for the correction of trophic enrichment factors. The simulation is demonstrated using a two‐isotope study (15N, 13C) of an Australian freshwater food web.
A robust modification of the ordered-heterogeneity test

Abstract An ordered heterogeneity (OH) test is a test for a trend that combines a non-directional heterogeneity test with the rank-order information specified under the alternative. We propose two modifications of the OH test procedure: (1) to use the mean ranks of the groups rather than the sample means to determine the observed ordering of the groups, and (2) to use the maximum correlation out of the 2k − 1 – 1 possibilities under the alternative rather than the single ordering (1, 2, … , k), where k is the number of independent groups. A simulation study indicates that these two changes increase the power of the ordered heterogeneity test when, as common in practice, the underlying distribution may deviate from a normal distribution and the trend pattern is a priori unknown. In contrast to the original OH test, the modified OH test can detect all possible patterns under the alternative with a relatively high power.
Constrained Ruled Surface Reconstruction for 5-Axis NC Machining of Aero-Structure

We proposed a constrained ruled surface approximation algorithm for 5-axis machining of aero structure. Ruled surface is widely used in the design of aero structure. In practical model process, the regular ruled surface is usually split into some small fragmentary surfaces. The segmentation of the original surface mainly comes from some iterative boolean operations on the ruled surface. The segmentation destroys original parameter lines and leads into complex curved boundaries. Furthermore, the obtained fragmentary surfaces deviate from the original ruled surface because of the accuracy loss in the boolean operations of 3D CAD software. Some gaps between the small surfaces often appear. In manufacturing process, it is difficult to generating high-quality tool path for the surface with disordered parameter lines, curved boundaries and gaps. The proposed ruled surface approximation algorithm provides an effective way to reconstruct the smooth ruled surface. The constraints of boundary and smoothness are both considered. The ruled surface for simultaneous 5-axis machining is finally obtained. This algorithm have been integrated into CATIA V5 system and applied in practical manufacturing planning of aero-structures.