Miracle-dz/UniFAR-FTUs huggingface dataset:
Fullerene C70 as a p-type donor in organic photovoltaic cells

Fullerenes and their derivatives have been widely used as n-type materials in organic transistor and photovoltaic devices. Though it is believed that they shall be ambipolar in nature, there have been few direct experimental proofs for that. In this work, fullerene C70, known as an efficient acceptor, has been employed as a p-type electron donor in conjunction with 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile as an electron acceptor in planar-heterojunction (PHJ) organic photovoltaic (OPV) cells. High fill factors (FFs) of more than 0.70 were reliably achieved with the C70 layer even up to 100 nm thick in PHJ cells, suggesting the superior potential of fullerene C70 as the p-type donor in comparison to other conventional donor materials. The optimal efficiency of these unconventional PHJ cells was 2.83% with a short-circuit current of 5.33 mA/cm2, an open circuit voltage of 0.72 V, and a FF of 0.74. The results in this work unveil the potential of fullerene materials as donors in OPV devices, and pro.
Grassmann Numbers and Clifford-Jordan-Wigner Representation of Supersymmetry

The elementary particles of Physics are classified according to the behavior of the multi-particle states under exchange of identical particles: bosonic states are symmetric while fermionic states are antisymmetric. This manifests itself also in the commutation properties of the respective creation operators: bosonic creation operators commute while fermionic ones anticommute. It is natural therefore to study bosons using commuting entities (e.g. complex variables), whereas to describe fermions, anticommuting variables are more naturally suited. In this paper we introduce these anticommuting- and at first sight unfamiliar- variables (Grassmann numbers) and investigate their properties. In particular, we briefly discuss differential and integral calculus on Grassmann numbers. Work supported in part by DOE contracts No. DE-AC-0276-ER 03074 and 03075; NSF Grant No. DMS-8917754.
An improved multi-scale autoconvolution transform

Affine invariant feature computing method is an important part of statistical pattern recognition due to the robustness, repeatability, distinguishability and wildly applicability of affine invariant feature. Multi-Scale Autoconvolution (MSA) is a transformation proposed by Esa Rathu which can get complete affine invariant feature. Rathu proved that the linear relationship of any four non-colinear points is affine invariant. The transform is based on a probabilistic interpretation of the image function. The performance of MSA transform is better on image occlusion and noise, but it is sensitive to illumination variation. Aim at this problem, an improved MSA transform is proposed in this paper by computing the map of included angle between N-domain vectors. The proposed method is based on the probabilistic interpretation of N-domain vectors included angle map. N-domain vectors included angle map is built through computing the vectors included angle where the vectors are composed of the image point and its N-domain image points. This is due to that the linear relationship of included angles between vectors composed of any four non-colinear points is an affine invariance. This paper proves the method can be derived in mathematical aspect. The transform values can be used as descriptors for affine invariant pattern classification. The main contribution of this paper is applying the N-domain vectors included angle map while taking the N-domain vector included angle as the probability of the pixel. This computing method adapts the illumination variation better than taking the gray value of the pixel as the probability. We illustrate the performance of improved MSA transform in various object classification tasks. As shown by a comparison with the original MSA transform based descriptors and affine invariant moments, the proposed method appears to be better to cope with illumination variation, image occlusion and image noise.
High efficiency semimetal/semiconductor nanocomposite thermoelectric materials

Rare-earth impurities in III–V semiconductors are known to self-assemble into semimetallic nanoparticles which have been shown to reduce lattice thermal conductivity without harming electronic properties. Here, we show that adjusting the band alignment between ErAs and In0.53Ga0. 47−XAlXAs allows energy-dependent scattering of carriers that can be used to increase thermoelectric power factor. Films of various Al concentrations were grown by molecular beam epitaxy, and thermoelectric properties were characterized. We observe concurrent increases in electrical conductivity and Seebeck coefficient with increasing temperatures, demonstrating energy-dependent scattering. We report the first simultaneous power factor enhancement and thermal conductivity reduction in a nanoparticle-based system, resulting in a high figure of merit, ZT=1.33 at 800 K.
Mixture analysis using factor analysis. II: Self‐modeling curve resolution

One of the major applications of factor analysis in the chemical literature, self‐modeling curve resolution (SMCR), is covered in this review, including a historical account of the methods derived from Lawton and Sylvestre's original method. Papers treating the theory or applications of SMCR are included. Qualitative and quantitative applications are described where appropriate.
Brief review of primary methods applicable to key comparisons in acoustics

Historically, various techniques have been used in acoustics to attempt to establish and measure sound pressures (spatially uniform amplitude of sound pressure, as in a suitable coupling cavity that is small compared with a wavelength of sound) and in the free field (plane progressive sound wave at a specified angle of incidence, in the absence of reflecting surfaces). At present, over a broad range of frequencies the most accurate, precise, and convenient methods involve the primary calibrations of laboratory standard microphones by reciprocity techniques. Some issues and parameters in these techniques that must be considered in comparisons, and selected previous interlaboratory comparisons themselves, are discussed. Recommendations relevant to a key comparison already identified, as well as future work areas, are presented.
Probabilistic formulation of damage-evolution law of cementitious composites

A model is proposed with a probabilistic evolution of damage in the material. The constitutive law is built through the development of a two-level approach. The micro-level is assumed to be constituted of elastic-brittle springs whose strength follows a probabilistic distributin. The representative macro-volume of material contains a given number of these elementary defects and its damage (loss of elastic properties) is computed from the knowledge of the local states. The macro-behavior results from the interactions between all the micro-defects. The model may be considered as representative of the behavior of brittle and almost brittle materials. It exhibits scattering and size effect. A Weibull distribution law is assumed for the local probabilities of failure and a parallel loose bundle connects the micro-defects. These simple hypotheses lead to analytical expressions of the probabilistic constitutive law. The approach developed appears as an intermediate model between continuous damage mechanics and probabilistic brittle fracture. The knowledge of a single parameter \IN\N\dt, number of defects in a given volume, provides the degree of ductility of the material.
Application of passivity and cascade structure to robust control against loss of actuator effectiveness

In this paper the problem studied is passive fault tolerant control with respect to loss of actuator effectiveness, for nonlinear models. The main idea of the work is the formulation of the faulty models as cascade systems of the healthy models with the fault models. Based on this simple formulation, passivity theory is used to ensure the stability of the faulty system. We also study the problem of input saturation. The type of faults studied here are constant as well as time‐varying faults. The validity of the proposed controllers is shown on several numerical examples. Copyright © 2009 John Wiley & Sons, Ltd.
Ultra-sensitive, room-temperature THz detection based on parametric upconversion by using a pulsed 1550nm optical source

We demonstrate ultra-sensitive optical detection of terahertz by using nonlinear parametric upconversion. Terahertz radiation is mixed with pump light at 1550 nm in a nonlinear crystal to generate an optical sideband or idler wave. The idler signal is separated from the optical pump, coupled into an optical fiber and detected using a Geiger-mode avalanche photo-diode. Our scheme to detect THz waves leverages mature technology at 1550 nm developed for telecommunications to enable ultra-sensitive detection at room-temperature. We have fabricated a diffusion-bonded, quasi phasematched GaAs crystal, a χ(2) nonlinear material, that is pumped with a readily obtainable erbium doped fiber amplifier to perform the parametric conversion. We demonstrate efficient upconversion of terahertz radiation using both a continuous-wave THz source operating at 0.82 THz and a pulsed sub-picosecond THz source with spectral coverage from 0.5 THz to 1.5 THz. The resulting THz detector has a noise equivalent power of 78 fW/Hz1/2 with a timing resolution of 1 ns. χ(2) nonlinear interactions are intrinsically very fast; our temporal bandwidth is limited by the optical detector. Additionally, the THz detector demonstrates a broadband response with a phase-matching bandwidth exceeding 1 THz. This noise equivalent power of 78 fW/Hz1/2 and the corresponding power conversion efficiency of 1.2× 10-3 are the best reported, to our knowledge. This paper presents both theoretical and experimental results.
Compton scatter effects in CT reconstructions

Compton scatter of x‐ray quanta is the dominant attenuation mechanism in medicaldiagnosticimaging. In this paper, it is shown that the scatter‐to‐primary ratio determines the nature and intensity of scatter artifacts in computed tomography(CT)reconstructions and that this ratio, while significantly lower than in radiographic and fluoroscopic examinations, can still be significant in CT. It is found that high spatial‐frequency artifacts can arise even though the detected scatter intensity has little or no high‐frequency modulation. Reconstructions from x‐ray data are presented which show ‘‘cupping’’ as well as dark streaks connecting high‐attenuation regions. Correction of the data from measurements of scatter eliminates these artifacts. It is, moreover, observed that the intensity of the artifacts is often diminished when a beam‐shaping attenuator is employed. Calculations of scatter intensity are developed from a model which includes single‐event and two‐event scatter. This analysis is in good agreement with measurements on round water phantoms. Extension to other detector geometries shows, not unexpectedly, that detectors with poorer collimation yield larger scatter artifacts.
Mechanical elasticity of single and double clamped silicon nanobeams fabricated by the vapor-liquid-solid method

Atomic force microscopy has been used to characterize the mechanical elasticity of Si nanowires synthesized by the vapor-liquid-solid method. The nanowires are horizontally grown between the two facing Si(111) sidewalls of microtrenches prefabricated on a Si(110) substrate, resulting in suspended single and double clamped nanowire-in-trench structures. The deflection of the nanowires is induced and measured by the controlled application of normal forces with the microscope tip. The observed reversibility of the nanowire deflections and the agreement between the measured deflection profiles and the theoretical behavior of single and double clamped elastic beams demonstrate the overall beamlike mechanical behavior and the mechanical rigidity of the clamping ends of the nanowire-in-trench structures. These results demonstrate the potential of the nanowire-in-trench fabrication approach for the integration of VLS grown nanostructures into functional nanomechanical devices.
Sensors: A Comprehensive Survey

This book can be divided into two parts. The first, consisting of sensor-relevant micro and nanotechnological aspects, deals with materials in nanotechnology and discusses future tendencies in this field. The development in this sensor field is highly influenced by the rapid progress in solid-state physics, new transducer technologies, materials research and the technological application of quantum effects. The book gives an account of this trend. It begins with non-IC and IC technologies, proceeds with acoustic-wave devices, high-temperature microsensors, integrated optical sensors and optical microsensors and ends with molecular sensors and nanotechnology. These selected aspects of sensor science describe the state of the art and, in part, the future trends in this field. Without doubt microsensors or nanosensors play, and will continue to play, an important role in many areas, e.g. in medicine, microreactors used in pharmacy and automotive applications, but as yet they represent only a relatively small part of the whole sensor family. Nevertheless the information on new technologies, new materials and new sensors is important for every researcher, engineer in industry and sensor user. The value of the first part of this book lies in the concentrated summary of this new sensor field. The second part of the book, consisting of chapters 12 to 18, presents information on the sensor market. It covers areas such as aerospace, process control, medicine, environmental monitoring, automotive control and manufacturing technology. Such information is not only meaningful for industry managers, but also for scientists dealing with sensor development and considering new sensor applications. This section of the book gives a different approach to the field - it does not deal only with micro and nanosensors and it is not written in a scientific manner. Presumably the reader of part one is not very often the reader of part two, and vice versa, but such an approach is welcome in the fast developing field of sensor research and application. This book, volume 8 of the Sensors series, is the continuation of a good tradition, namely the published volumes 1 to 7 of Sensors, which have been devoted to different types of sensors from the viewpoint of known principles, techniques and well tested materials. This volume goes beyond this frontier. It is warmly recommended to everyone working, or interested in, sensor research and applications.
Random Approximants and Neural Networks

LetDbe a set with a probability measure? ,? (D)=1, and letKbe a compact subset ofLq(D, ? ), 1? q<∞. Forf? Lq,n=1, 2, ? , let? n(f, K)=inf? f? gn? q, where the infimum is taken over allgnof the formgn=? ni=1ai? i, with arbitrary? i? Kandai? R. It is shown that forformula], under some mild restrictions,? n(f, K)? Cq? n(K)n? 1/2, where? n(K)? 0 asn? ∞. This fact is used to estimate the errors of certain neural net approximations. For the latter, also the lower estimates of errors are given.
First inelastic x‐ray scattering spectroscopy measurements of the dynamic structure factor S(q,ω) of electrons in a solid noble gas (He)

Inelastic x‐ray scattering spectroscopy measurements on hcp single crystal solid He with q∥c axis and q=0.45, 0.97, and 1.24 a.u. are presented. The crystals were grown in situ under a pressure of 600 bar at 5–7 K within a Be hollow cylinder. By subtracting a measurement on the empty Be cylinder, pure solid He spectra are obtained and discussed in terms both of the hcp He band structure and of excitonic excitation. The existence of an exciton at 21.8 eV above the 1s core level could unambiguously be settled. Clear evidence is found that the bottom of the conduction band is at 27 eV.
Expanders and diffusers

Expander graphs are ingredients for making concentrating, switching, and sorting networks, and are closely related to sparse, doubly-stochastic matrices called diffusers. The best explicit examples of diffusers are defined by means of the action of elements of the matrix group $SL (2,{\bf Z} )$ on certain finite mathematical objects. Some corresponding, explicit expanders were introduced by Margulis. However, Gabber and Galil were the first to obtain good estimates for the expanders and produce from them a family of directed acyclic superconcentrators having density 271.8. In this paper we review various techniques for making expanders from diffusers. We also demonstrate asymptotic upper bounds on the strength of algebraically defined classes of degree k diffusers. Each upper bound is given as the norm of a diffusion operator on an infinite discrete group, and bounds for several examples are calculated. Numerical evidence is supplied in support of our conjecture that these bounds can be achieved by certai.
No evidence for radio-quiet BL Lacertae objects

Using a large, flux-limited sample of faint X-ray sources, a search has been conducted for radio-quiet BL Lacertae objects. None has been found. Thirty-two X-ray-selected BL Lac objects and BL Lac candidates have been found within the sources of the Einstein Medium Sensitivity Survey (EMSS). Thirty-one of these have been observed with the VLA and all have been detected at 5 GHz. While the optical magnitudes of the EMSS BL Lac objects range from 17 to 20.8, their radio-to-optical spectral indices occupy a very small range. The very bright X-ray-selected BL Lac objects like PKS 2155-304 and Markarian 501 have similar range values. Therefore, unlike the clear dichotomy between radio-loud quasars and radio-quiet QSOs, there is no evidence for two populations of Lacertids distinguished by radio loudness. 43 refs.
Modeling of Electrokinetically Driven Flow Mixing Enhancement in Microchannels with Patterned Heterogeneous Surface and Blocks

Mixing in microchannels is an important process since certain microfluidic applications require the rapid mixing of species. This paper investigates the mixing in the microchannels via the possibility of utilising the spatial zeta potential variations with the opposite sign to that of the homogeneous surface to create the circulation zones within the bulk flow. The effects of the number of heterogeneous patches, the strength of applied external voltage and zeta potential are analyzed to determine the mixing efficiency. In addition, the replacement of patches with heterogeneous surface blocks shows the improvement of mixing efficiency. The fluid flow is simulated via the single relaxation time lattice Boltzmann method (LBM) with a forcing term from the electric field. The concentration of species within the channel is governed by an advection‐diffusion equation with Peclet number of the order 1000.
A framework for moment equations for magnetized plasmas

Mathematical formalism to solve a system of general moment equations [J.-Y. Ji and E. D. Held, Phys. Plasmas 13, 102103 (2006); 16, 102108 (2009)] for magnetized plasmas is presented. A series of ordered moment equations are written using a perturbative expansion based on large cyclotron frequency. For the most general solution, formulas for homogeneous and particular solutions are obtained. These formulas generalize the CGL [G. F. Chew et al., Proc. R. Soc. London, Ser. A 236, 112 (1956)] and non-CGL [C. T. Hsu et al., Phys. Fluids 29, 1480 (1986)] tensors, respectively, from rank-2 to arbitrary rank. The parallel moment equations to determine parallel moments in the homogeneous solution are derived. The formalism can be applied to plasmas of general collisionality and magnetic geometry with accurate collision operators provided.
Integrity of thin, laser-driven flyer plates

Laser-driven flyers were launched from substrate backed aluminum films. They were produced by single pulses from a Q-switched Nd:yttrium–aluminum–garnet laser, of 10 ns duration and typically up to a few hundred mJ energy, with a focused spot size of approximately 1 mm diameter. The aluminum films were between 2 and 6 μm thick and the flyers typically achieved average velocities of a few km s−1. The integrity of the flyers was studied using streak photography and microscopy of the impacted flyers. Threshold times and distances prior to plasma penetration were used as a measure of integrity and were calculated for films of different thickness, launched with various laser pulse energies.
Monopoles and dyons in the SU(5) model

The spherically symmetric monopoles and dyons of the SU(5) model of grand unification (without quarks and leptons) are discussed. It is shown that such monopoles and dyons can exist only in the sectors corresponding to magnetic charges m= +- 1/2e, +- 1/e, +- 3/2e, and +- 2/e, where e is the charge of the positron. We investigate in detail the properties of the dyons with the smallest possible magnetic charge ( vertical-barmvertical-bar=1/2e). By semiclassical reasoning we show that apart from the magnetic charge the properties of the dyons are described by two quantum numbers n and k. The dyons come in families, denoted by n=0,1,2,. , with electric charge q/sub n/=n(-4e/3), baryon minus lepton number =n(-2/3), and the kth member of the nth family (k=0,1,2,.) transforms according to the (n+k,k) for n > or = 0 or the (k,vertical-barnvertical-bar+k) for n or = 0, or vertical-barnvertical-bar 3's, for n<0. Interesting processes involving monopoles and dyons are discussed; we show, for example, that the presence of a dyon strongly enhances baryon-number-violating processes. Finally, a less detailed discussion of poles with the other possible magnetic charges is included. « less
Spatial Studies of Planetary Nebulae with IRAS

The infrared sizes at the four IRAS wavelengths of 57 planetaries, most with 20-60 arcsec optical size, are derived from spatial deconvolution of one-dimensional survey mode scans. Survey observations from multiple detectors and hours confirmed (HCON) observations are combined to increase the sampling to a rate that is sufficient for successful deconvolution. The Richardson-Lucy deconvolution algorithm is used to obtain an increase in resolution of a factor of about 2 or 3 from the normal IRAS detector sizes of 45, 45, 90, and 180 arcsec at wavelengths 12, 25, 60, and 100 microns. Most of the planetaries deconvolve at 12 and 25 microns to sizes equal to or smaller than the optical size. Some of the planetaries with optical rings 60 arcsec or more in diameter show double-peaked IRAS profiles. Many, such as NGC 6720 and NGC 6543 show all infrared sizes equal to the optical size, while others indicate increasing infrared size with wavelength. Deconvolved IRAS profiles are presented for the 57 planetaries at nearly all wavelengths where IRAS flux densities are 1-2 Jy or higher. 60 refs.
The Canadian Regional Data Assimilation and Forecasting System

Abstract This paper describes the recent changes to the regional data assimilation and forecasting system at the Canadian Meteorological Center. A major aspect is the replacement of the currently operational global variable resolution forecasting approach by a limited-area nested approach. In addition, the variational analysis code has been upgraded to allow limited-area three- and four-dimensional variational data assimilation (3D- and 4DVAR) analysis approaches. As a first implementation step, the constraints were to impose similar background error correlation modeling assumptions, equal computer resources, and the use of the same assimilated data. Both bi-Fourier and spherical-harmonics spectral representations of background error correlations were extensively tested for the large horizontal domain considered for the Canadian regional system. Under such conditions, it is shown that the new regional data assimilation and forecasting system performs as well as the current operational system and it produc.