Miracle-dz/UniFAR-FTUs huggingface dataset:
Dye laser induced fluorescence of plasmas and its application to measurement of lower state decay rates

A simple but powerful extension of fluorescence scattering methods for the measurement of decay rates is described together with results of an experiment on a helium plasma. The technique should allow measurements of A-values and excitation rates for vacuum UV transitions from observations of visible fluorescence, and reduces the need for short pulse lasers for decay rate measurements.
Recent experimental studies of electron dephasing in metal and semiconductor mesoscopic structures

In this review, we discuss the results of recent experimental studies of the low-temperature electron dephasing time (τφ) in metal and semiconductor mesoscopic structures. A major focus of this review is on the use of weak localization, and other quantum-interference-related phenomena, to determine the value of τφ in systems of different dimensionality and with different levels of disorder. Significant attention is devoted to a discussion of three-dimensional metal films, in which dephasing is found to predominantly arise from the influence of electron–phonon (e–ph) scattering. Both the temperature and electron mean free path dependences of τφ that result from this scattering mechanism are found to be sensitive to the microscopic quality and degree of disorder in the sample. The results of these studies are compared with the predictions of recent theories for the e–ph interaction. We conclude that, in spite of progress in the theory for this scattering mechanism, our understanding of the e–ph interaction remains incomplete. We also discuss the origins of decoherence in low-diffusivity metal films, close to the metal–insulator transition, in which evidence for a crossover of the inelastic scattering, from e–ph to ‘critical’ electron–electron (e–e) scattering, is observed. Electron– electron scattering is also found to be the dominant source of dephasing in experimental studies of semiconductor quantum wires, in which the effects of both large- and small-energy-transfer scattering must be taken into account. The latter, Nyquist, mechanism is the stronger effect at a few kelvins, and may be viewed as arising from fluctuations in the electromagnetic background, generated by the thermal motion of electrons. At higher temperatures, however, a crossover to inelastic e–e scattering typically occurs; and evidence for this large-energy-transfer process has been found at temperatures as high as 30 K. Electron–electron interactions are also thought to play an important role in dephasing in ballistic quantum dots, and the results of recent experiments in this area are reviewed. A common feature of experiments, in both dirty metals 3 Authors to whom any correspondence should be addressed.
Monopole antenna for GSM, Bluetooth, and UWB applications with dual band-notched characteristics

A novel multi-band planar monopole antenna for various wireless communication applications is presented. The base of the proposed antenna is an ellipse-shaped patch that covers the ultrawideband (UWB) frequency range. To create extra frequency bands below the UWB band, two narrow quarter-wavelength strips are attached to the high concentrated current area of the patch. Two notched bands, centred at 3.5 GHz WiMAX and 5.5 GHz WLAN, are also created by similarly integrating strips to the radiation patch. The proposed multi-band antenna has a small size of 30 × 30 mm2 and covers GSM (1.77–1.84 GHz), Bluetooth (2.385–2.49 GHz) and UWB (3.1–10.6 GHz) bands. Simulated and measured results are presented and compared, which show that the antenna has omnidirectional and stable radiation patterns across the entire passband. Furthermore, good group delay and transmission characteristics can be achieved in the UWB band.
A mixed Lagrangian-Eulerian approach to modelling fluid flow during mould filling

An updated free surface Lagrangian-Eulerian finite element kinematic description is used to simulate free surface flow problems associated with mould filling. The method proposed results in an accurate determination of the front, making it ideal for problems in which free surface boundary conditions play an important role. Significant saving in CPU time can be obtained over other fixed mesh approaches by virtue of the air domain being ignored. Assuming a laminar regime for the flow field, a mixed interpolation formulation is used to approximate the discretized governing equations for elimination. Of particular interest is the method implementation to restrict the number of remeshing operations and track the moving free surface within an arbitrary domain, either with or without internal obstacles. The method used to automatically assign boundary conditions to the changing domain is described. A dam break problem is modelled numerically and compared against experimentally derived data in order to validate the model. A further numerical example demonstrates the capabilities of the algorithm developed to model the filling of an industrial casting.
Blast wave and contraction in Au(111) thin film induced by femtosecond laser pulses. A time resolved x-ray diffraction study.

We utilize 100 fs optical pulses as a means of heating 150 nm thick single Au (111) crystals, below the melting point and monitor the subsequent structural evolution with subpicosecond time resolution using 0.6 ps, 8.04 KeV x-ray pulses. By monitoring the energy and time dependent modulation of the width and shift of the x-ray diffraction rocking curve, we have obtained information on electron-phonon coupling, photon-lattice interaction, and time resolved kinetics of the crystal disorder. The data show that during the first couple picoseconds after optical excitation, the formation of a “blast force” and lattice contraction, followed by a pressure wave formed 10-20 ps later. Both the blast and pressure wave propagate through the crystal with sonic velocities. These time resolved x-ray diffraction data provide a detail description of the processes induced by ultrafast laser pulses impinging on very thin metallic crystals.
Response times to conceptual questions

We measured the time taken by students to respond to individual Force Concept Inventory (FCI) questions. We examine response time differences between correct and incorrect answers, both before and after instruction. We also determine the relation between response time and expressed confidence. Our data reveal three results of interest. First, response times are longer for incorrect answers than for correct ones, indicating that distractors are not automatic choices. Second, response times increase after instruction for both correct and incorrect answers, supporting the notion that instruction changes students' approach to conceptual questions. Third, response times are inversely related to students' expressed confidence; the lower their confidence, the longer it takes to respond.
Development of Computational Aeroacoustics Tools for Airframe Noise Calculations

This paper discusses the development of computational aeroacoustics (CAA) tools for airframe noise analysis and prediction. We review recent progress in this topic, but emphasize our vision for the future development of such tools. Our intention is for this vision to drive future CAA research in directions that will accelerate widespread use of CAA for airframe noise applications. We discuss the needs for accuracy, efficiency, and easy interface with other design tools and illustrate how CAA tools may help future aircraft design. We explain what appears to be achievable in a 20-year time frame, and what goals will probably take longer. Important barrier issues include the effects of numerical dispersion and dissipation, the treatment of highly curved, irregular boundary surfaces, and grid generation. Beyond these largely numerical issues, we discuss the role of physics-based modeling, including turbulence modeling in unsteady flow computations and the importance of developing sophisticated techniques for analyzing results of computations. Numerical simulations combined with the acoustic analogy methodology to predict noise are also reviewed. Finally, we discuss how to use recent advances in measurement techniques for CAA tool validation, which is an integral part of future development.
A study of bias for various iterative reconstruction methods in PET

In this work the level of positive bias in images generated by various iterative reconstructions of low activity PET data was investigated. A 3D acquisition of a low activity cylinder was performed upon an EXACT3D PET scanner followed by a multi-trial single plane simulation based upon this scan, taking into account randoms, scatter and attenuation. These were reconstructed using different implementations of maximum likelihood expectation maximisation, including the simple case of fully precorrected data and also using a separate randoms estimate with the shifted Poisson and prompts approaches. The effect of estimating the mean of randoms from the noisy delayed randoms with a maximum likelihood technique was also investigated.
Composition of Foreground and Background Images using Optical Flow and Weighted Border Blending

스마트폰의 전면 및 후면 카메라를 이용하여 동시에 획득한 전경 이미지와 배경 이미지에서, 전경 이미지의 일부분인 전경 물체를 추출하여 배경 이미지에 합성하는 방법을 제시한다. 최근의 고사양 스마트폰은 대개 두 개의 카메라를 가지고 있고, 사진을 촬영하는 과정에서 미리보기 화면을 제공한다. 전면 카메라로부터 전경 이미지를 획득하는 과정에서 미리보기 화면의 비디오에 대한 옵티컬 플로우를 이용하여 전경 물체를 추출한다. 추출된 전경 물체와 배경 화면을 단순히 합성한 후, 전경 물체와 배경화면의 경계에서 가중치 경계 블렌딩을 이용하여 시각적으로 부드러운 경계를 갖는 합성을 수행한다. 화소 수준의 조밀한 옵티컬 플로우의 계산은 고사양의 스마트폰에서도 상당히 느리기 때문에, 전경 물체 추출을 위한 마스크의 계산을 저해상도에서 수행하여 계산시간을 크게 절약 할 수 있다. 실험적 결과에 의하면 제안하는 방법은 더 적은 계산 시간을 사용하며, 널리 사용되는 Poisson 이미지 합성 방법에 비하여 시각적으로 더 우수한 결과를 얻을 수 있다. 제안하는 방법은 Poisson 이미지 합성 방법에서 자주 관찰되는 색 번짐 결점을 가중치 경계 블렌딩을 이용하여 제한적인 수준에서 극복할 수 있다.
Trajectory Prediction for Light Aircraft

In this paper, a novel algorithm for estimation, filtering, and prediction of trajectories of light aircraft and gliders based on Global Positioning System measurements is introduced. The algorithm uses interacting-multiple-model filters to detect specific maneuvers such as turning, circling, or straight flight. An integrated wind model allows for quick estimation of the local wind field and helps to achieve consistently good prediction accuracy in windy conditions. The algorithm is shown to perform well compared with legacy algorithms currently used in a collision avoidance system.
A multioctave coaxially oriented beam‐resonator arrangement Fourier‐transform microwave spectrometer

The design, performance, and operation of a broadband (3–26.5 GHz) high resolution microwave spectrometer is described. In comparison to previously developed molecular beam Fabry–Perot resonator spectrometers the design presented here implements some significant improvements: a coaxially oriented beam resonator arrangement (COBRA) formed by a confocal pair of mirrors incorporating an electromechanical valve and employing two pairs of microwave antennas, and a multioctave Fourier‐transform microwave (FTMW) instrument providing the pulsed excitation source with microwave pulse phase‐inversion scheme and the low‐noise receiving system employing image‐rejection downconversion with superheterodyne as well as quadrature detection. The entire apparatus, fully automated for scanning operation, covers a frequency range of more than three octaves. The novel design of the FTMW instrument does not require any changes of the spectrometer hardware in order to reach all regions of its spectral range. While operated in h.
Lithization of the FTU tokamak with a critical amount of lithium injection

FTU plasma discharges with an extremely high amount of Li injection have been performed using a poloidal liquid lithium limiter acting as the principal Li source in the shadow of the main TZN toroidal limiter. Very peculiar of these discharges is the formation of a ‘virtual’ toroidal lithium limiter that redistributes the energy flux to the tokamak vessel first wall by radiative processes and therefore decreases the heat load onto the Mo limiter. These experiments contribute to the investigation of a more complex scenario that will possibly be faced by a project of a liquid lithium divertor in a tokamak with high additional power (or high power load on to the targets).
Conformal normal curvature and assessment of local influence

In 1986, R. D. Cook proposed differential geometry to assess local influence of minor perturbations of statistical models. We construct a conformally invariant curvature, the conformal normal curvature, for the same purpose. This curvature provides a measure of local influence ranging from 0 to 1, with objective bench‐marks to judge largeness. We study various approaches to using the conformal normal curvature and the relationships between these approaches.
Mueller matrix of a dicot leaf

A better understanding of the information contained in the spectral, polarized bidirectional reflectance and transmittance of leaves may lead to improved techniques for identifying plant species in remotely sensed imagery as well as better estimates of plant moisture and nutritional status. Here we report an investigation of the optical polarizing properties of several leaves of one species, Cannabis sativa, represented by a 3x3 Mueller matrix measured over the wavelength region 400-2,400 nm. Our results support the hypothesis that the leaf surface alters the polarization of incident light - polarizing off nadir, unpolarized incident light, for example - while the leaf volume tends to depolarized incident polarized light.
Measurement of internal magnetic field pitch using Li pellet injection on TFTR (invited)

A diagnostic technique which measures the direction of the internal magnetic field pitch angle has been used successfully on TFTR. The technique requires the injection of high‐speed Li pellets. The magnetic field direction is measured by observing the polarization direction of the intense visible line emission from Li+ (λ≊5485 A, 1s2p 3P0,1,2→1s2s 3S0) in the pellet ablation cloud. The presence of the large (primarily toroidal) magnetic field causes the line to be split due to the Zeeman effect, and the unshifted π component is polarized with its polarization direction parallel to the local magnetic field. In devices with sufficiently strong fields (B≳4.5 T), the Zeeman splitting of the line is large enough, relative to the linewidth of each Zeeman component, that enough residual polarization remains. Because the pellet moves about 1 cm before the Li+ is ionized (τionization≲10 μs), the time history of the polarization direction (as the pellet penetrates from the outside toward the plasma center) yields t.
Multi-fluid modelling of laminar polydisperse spray flames: origin, assumptions and comparison of sectional and sampling methods

A first attempt at deriving a fully Eulerian model for polydisperse evaporating sprays was developed by Tambour et al with the so-called sectional approach. However, the complete derivation of the sectional ‘multi-fluid’ conservation equations from the Boltzmann-type spray equation was never provided, neither was the set of underlying assumptions nor the comparison with the classical Lagrangian model: the sampling method. In this paper, we clarify the set of assumptions necessary in order to derive the multi-fluid sectional model from the spray equation at the ‘kinetic level’ and provide the derivation of the whole set of conservation equations describing the dispersed liquid phase. Whereas the previous derivation is conducted in any space dimension, we restrict ourselves to one-dimensional stationary flows where the droplets do not turn back and derive a Eulerian sampling model which is equivalent in this context to the usual Lagrangian particle approach. We then identify some situations, even within this restrictive framework, where the sectional approach fails to reproduce the coupling of the vaporization and dynamics of the spray, the sampling method then being required. In the domain of applicability of the sectional approach, the two methods are then compared numerically in the configuration of counterflow spray diffusion flames. The two methods, if refined enough, give quite similar results, except for some small differences, the origin of which is identified. It is proved that the sampling method is more precise even if it generates oscillations due to the intrinsic representation of a continuous function by Dirac delta functions. We thus provide a comprehensive analysis of the sectional approach from both the modelling and numerical points of view.
Microscopic model for the nonlinear behavior of high-k metal-insulator-metal capacitors

The achievement of sufficient capacitance-voltage linearity in metal-insulator-metal (MIM) capacitors with high permittivity (high-k) dielectrics is still a challenge, as the origin of the nonlinear behavior is still unclear. Based on fundamental physical mechanisms, such as electrostriction, Coulomb interaction between electrodes, and nonlinear optical effects, a microscopic model, which describes the nonlinearities in capacitance-voltage characteristics of high-k MIM capacitors, will be presented. The extended model, which includes stacked high-k dielectrics and interfacial layers, is able to predict the quadratic voltage capacitance coefficients as a function of the dielectric constant. The calculated coefficients are in suitable agreement with the experimental values of Al2O3-, Y2O3-, HfO2-, and Pr2Ti2O7-based MIM capacitors.
Generalized Impulse Response Analysis in a Fractionally Integrated Vector Autoregressive Model

We develop a generalized impulse response function for the fractionally integrated vector autoregressive (FIVAR) model using the Pesaran and Shin (1998) approach. Our method is different from the methodology shown in Chung (2001) since it does not require us to orthogonalize the error vector and, therefore, is independent of the ordering of the endogenous variables in the FIVAR. Being consistent with the long memory behaviour, we show that generalized and orthogonalized impulse responses of FIVAR evolve slowly at the same hyperbolic rates. However, we also note that they are different in a number of respects.
Theoretical Analysis of Closed Rankine Cycle Solar Pond Power Generator

Thermal energy extraction from solar pond is theoretically studied with the use of Rankine cycle heat engine. The Rankine power cycle configuration consists of evaporator, turbine, condenser, feed pump and R-134a which is used as the working fluid. A solar pond is considered as the heat source for the evaporator. Fresh water circulates through an internal heat exchanger, located in the lower convective zone of the pond, and transfers its thermal energy to evaporator. The heat that is absorbed increases the temperature of a working fluid and causes the working fluid to vaporize. When the working fluid has taken enough potential energy, the fluid vaporizes and begins to rise, thereby converting some of the potential energy to kinetic energy. The vapor flows under high pressure to the turbine and thereby expanding through the turbine from a higher pressure to a lower pressure. Useful work can be extracted from this expansion process. The turbine is placed in between the evaporator and condenser section of the cycle. The water is acting as heat sink for the condenser. An attempt is made to analyze the thermodynamic aspects of the cycle and the net works generated by the system are elaborated. The report presents the analysis of an alternative method of thermal energy extraction from solar energy thermal resource with the use of solar pond.
Highly Conductive p-Type Silicon Carbon Alloys Deposited by Hot-Wire Chemical Vapor Deposition

P-type microcrystalline silicon carbide (µc-SiC:H) alloys for application as a window layer in silicon based thin film solar cells were grown by hot-wire chemical vapor deposition using hydrogen diluted monomethylsilane and trimethylaluminum. Conductivities up to 0.1 S/cm were obtained for p-type material. The optical properties were studied by photothermal deflection spectroscopy. At photon energies below 1.25 eV, both free carrier and defect absorption lead to a high absorption coefficient. For photon energies >2.0 eV, the absorption coefficient is affected by the crystallinity and the structural composition. The structure of Al-doped µc-SiC:H thin films were investigated by infrared and Raman spectroscopy. It was found that increase of the deposition pressure can compensate for the loss of crystallinity caused by Al-doping. At high deposition pressure (>100 Pa), increasing contributions of hexagonal SiC alloys, and separated carbon phases are observed.
A new control chart based on the loess smooth applied to information system quality performance

Sometimes to measure the performance of an information system, unusually long response times of database operation need to be identified. Compared with Lloyd's (1995) statistical process control chart, we propose an outlier resistant robust locally weighted scatterplot smooth (loess) based control chart that identifies effectively all the out of control points of operation in Lloyd's (1995) data. Our findings provide guidance to management in information system quality control and more generally to all control chart users in cases where outliers occur in the charted data.
A tactile display of pitch period for use in sensory substitution

A real‐time tactile display of fundamental frequency was constructed. This device accepts a train of pitch‐synchronous pulses from a pitch extractor and feeds them to one of eight miniature solenoids. Frequency resolution is approximately 1/3 of an octave over a range of 1 1/2 octaves. With the solenoids spaced by 1/4 in. , and the index finger as the tactile input site, psychophysical studies showed excellent discrimination among normal English intonation contours and between normal and abnormal contours. The display is currently being used in a study of sensory aids with deaf children in which auditory, visual, and tactile inputs are being compared.
Stimulated scattering of an electromagnetic wave by an upper-hybrid wave in a two-electron-temperature plasma

We present an analytical investigation of the stimulated scattering of an electromagnetic wave by an upper-hybrid wave in a two-electron-temperature plasma using a hydrodynamical model. The nonlinear dispersion equation of the upper-hybrid wave is derived and the growth rate is calculated. It is found that increasing the concentration ratio of hot to cold electrons decreases the growth rate of the upper-hybrid wave.
Ontology-Based Semantic Similarity Measure with Concept Lattice

Semantic similarity measure has always been one of the important contents in artificial intelligence. This paper puts the ontology as the research object, and measure the semantic similarity between two ontologies in view of concept lattice. Firstly, concept lattice is introduced to similarity measure, and the thought of the ontology-based semantic similarity measure with concept lattice was given. Next, the solution of the measure was described, which includes generating a formal context of heterogeneous ontologies, constructing the corresponding formal context of formal context to fetch the formal context in concept lattice, and using irreducible infimum theory to calculate the similarity value of heterogeneous ontology concept. Finally, we employed a sample to verify the measure method. The results showed the method can effectively compute the semantic similarity between the ontologies, and the method proposed is valid and feasible.