Miracle-dz/UniFAR-FTUs huggingface dataset:
Measurement and analysis of defocused point spread functions and optical transfer functions of a microscope

The defocused point spread functions and optical transfer functions of a microscope were measured and analyzed. The main purpose of the analysis was to verify the accuracy of analytical approximations of these functions, which were presented but not extensively studied in the literature. The measured results were compared with those calculated by Castleman's (1979) theoretical approximation, in the space and frequency domains, graphically and numerically. The results showed that for the numerical apertures used, the theoretical functions were close to the measured functions, and thus Castleman's theoretical approximation is a fairly good approximation. These defocused point spread functions are being used for the optical sectioning as part of microscope image visualization system described by Li, Agathokils, Peet, Jensen and Sahota (see Proceedings of 1993 Canadian Conference on Electrical and Computer Engineering, p.1013-1016, Sept. 1993, Vancouver).
The status of high-power lasers and their applications in the battlefield

We review the status and applications of a defensive weapon based on high-power lasers in the battlefield. The laser weapon is a novel concept that utilizes a high-power laser beam to traverse the distance into incoming objects at the speed of light and then destroys or disables it. Various types of lasers and configurations are discussed in this review, including gas lasers, solid state lasers, fiber lasers, and the free-electron laser. We discuss various configurations, such as an airborne laser, diode pumped crystals, and disk lasers as well as heat-capacity lasers. Recent applications of ultrafast solid state lasers for nonlethal or low-collateral-damage applications are also presented.
On the Influence of sampling errors on the perception of spatial sound fields using spherical microphone arrays for auralization

Spherical microphone distributions allow a three dimensional sampling of the sound field in a room. These microphone array data can be used for auralization on various playback systems. The aim of auralization is the reproduction of the sampled spatial sound field in order to give the listener the impression of being in the measured room. Due to the discrete spatial sampling process spatial aliasing corrupts the measured data. Therefore the resulting auralization quality is affected in terms of its spatial characteristics. Subjective quality measures for the spaciousness of sound fields can be represented by source localization accuracy, the apparent source width (ASW) and the listener envelopment (LEV). These subjective features are strongly related to objective measures like interaural level and time differences (ILD and ITD) or the interaural cross correlation (IACC). In subjective listening tests the influence of sampling errors on the binaural reproduction of a sampled sound field is investigated. The results are correlated with ITD, ILD and with IACC in order to gain an objective quality measure for sound fields recorded wtih spherical microphone arrays. The investigations are based on real measurement data taking various directions of arrival and different rooms into account.
Analysis and synthesis of a printed array for satellite communication with moving vehicles

We describe a mobile communications antenna consisting of concentric rings of elliptically polarized circular patches. For certain sets of relative phases, optimization of geometry and excitation amplitudes by simulated annealing synthesizes a conical beam with a maximum at a desired /spl theta/ and satisfactory directivity within a desired /spl theta/ range. An example of a two-ring array 50 cm in diameter with directivity >3 dB between /spl theta/=35/spl deg/ and /spl theta/=50/spl deg/ is presented.
Generation of multiply-charged metal ions in vacuum arc plasmas

The status of experimental research aimed at enhancing the ion charge states in vacuum are plasmas is reviewed. Strong magnetic fields, high-current arc "spikes," and intense electron beams have been used, separately, to increase the metal ion charge states produced. For each method, systematic measurements of ion charge state distributions were made. Each method has its advantages and disadvantages and each method does result in an increase in the mean ion charge state by up to a factor of 2.4, in the work carried out to-date. The last method, use of An added intense electron beam for enhanced ion stripping, is the most effective and work in this direction is being pursued further.
Zero rest-mass fields including gravitation: asymptotic behaviour

A zero rest-mass field of arbitrary spin s determines, at each event in space-time, a set of 2s principal null directions which are related to the radiative behaviour of the field. These directions exhibit the characteristic ‘peeling-off' behaviour of Sachs, namely that to order r-k-1 (k = 0, . . . , 2s), 2s - k of them coincide radially, r being a linear parameter in any advanced or retarded radial direction. This result is obtained in part I for fields of any spin in special relativity, by means of an inductive spinor argument which depends ultimately on the appropriate asymptotic behaviour of a very simple Hertz-type complex scalar potential. Spin (s - ½) fields are used as potentials for spin s fields, etc. Several examples are given to illustrate this, In particular, the method is used to obtain physically sensible singularity-free waves for each spin which can be of any desired algebraic type. In part II, a general technique is described, for discussing asymptotic properties of fields in curved space-times which is applicable to all asymptotically flat or asymptotically de Sitter space-times. This involves the introduction of ‘points at infinity’ in a consistent way. These points constitute a hypersurface boundary I to a manifold whose interior is conformally identical with the original space-time. Zero rest-mass fields exhibit an essential conformal invariance, so their behaviour at ‘infinity’ can be studied at this hypersurface. Continuity at I for the transformed field implies that the ‘peeling-off’ property holds. Furthermore, if the Einstein empty-space equations hold near I then continuity at I for the transformed gravitational field is a consequence. This leads to generalizations of results due to Bondi and Sachs. The case when the Einstein-Maxwell equations hold near I is also similarly treated here. The hypersurface I is space-like, time-like or null according as the cosmological constant is positive, negative or absent. The technique affords a covariant approach to the definition of radiation fields in general relativity. If I is not null, however, the radiation field concept emerges as necessarily origin dependent. Further applications of the technique are also indicated.
Bifurcations with spherical symmetry

Bifurcations from spherically symmetric states can occur in many physical and biological systems. These include the development of a spherical ball of cells into an asymmetrical state and the buckling of a sphere under pressure. They also occur in the evolution of reaction–diffusion systems on a spherical surface and in Rayleigh–Benard convection in a spherical shell. Many of the behaviours of these systems can be explained by their underlying spherical symmetry alone. Using results from the area of mathematics known as equivariant bifurcation theory we can use group theoretical methods both to predict the symmetries of the solutions which are expected to result from bifurcations with symmetry and compute their stability. In this thesis both stationary and Hopf bifurcation with spherical symmetry are discussed. Firstly, using group theoretical techniques, the symmetries of the periodic solutions which can be found at a Hopf bifurcation with spherical symmetry are computed. This computation has been carried out previously but contains some errors which are corrected here. For one particular representation of the group of symmetries of the sphere the stability properties of the bifurcating branches of periodic solutions resulting from the Hopf bifurcation are analysed and a survey is carried out of other periodic and quasiperiodic solutions which can exist. Secondly, symmetry considerations are used to investigate the existence and stability properties of symmetric spiral patterns on the surface of a sphere which result from stationary bifurcations. It is found that in the case of the Swift–Hohenberg equation spiral patterns with one or more arms can exist and be stable on spheres of certain radii. Although one-armed spirals in the Swift–Hohenberg equation are stationary solutions, it is shown that generically one-armed spirals on spheres must drift.
Study of structural and spectroscopic characterization of co-doped ZnS Nanoparticles capped with L-Arginine

The aim of the present study was to prepare ZnS nanoparticles co-doped with Li+-Cs+, were synthesized using a chemical co-precipitation method. The ZnS-(Li+-Cs+) nanoparticle’s were capped with L- Arginine and reduced using sodium sulphide. The main advantage of this method is to synthesized semiconductor nanomaterial with wide band gap and nanoparticles are chemically stable over a long time. The as prepared nanoparticles were characterised by X-Ray Diffraction technique for phase analysis of the sample. Particle size is found in the range of 2 to 4 nm calculated by Debye Scherer method. XRD confirms the evolution of stable cubic zinc blend phase of ZnS nanoparticles. The strong interaction between the capping agent L- arginine, Zn and S is revealed from the Fourier Transform Infrared (FTIR) spectrum.
Five-Brane Lagrangian with Loop Corrections in Field-Theory Limit

Equations of motion and the Lagrangian are derived explicitly for dual D = 10, N = 1 supergravity considered as a field theory limit of a five-brane. It is used the mass-shell solution of heterotic string Bianchi identities obtained in the two-dimensional σ-model two-loop approximation and in the tree-level heterotic string approximation. As a result the dual supergravity Lagrangian is derived in the one-loop five-brane approximation and in the lowest six-dimensional σ-model approximation.
A Novel Chirped Bragg Grating Based Spectral Domain Delay Generator

Light dispersion and chirping of spectral lines of a broadband light source is major issue with spectral domain optical coherence tomography. We designed a novel spectral delay line using multimode interference coupler and chirp Bragg grating. We considered the waveguide material as S-1813 polymer. Light from the broad-band light source is first dispersed then delayed in time. The bunches of delayed spectra produce chirping. The design ensures that the bandwidth of each bunch is about 30nm linewidth at a central wavelength of 1. 55µm, corresponding to a coherence length of 15µm. The design is optimized for maximum dispersion with (i) minimum possible number of Bragg gratings and (ii) low attenuation and radiative losses. Tolerance measurements for differential refractive index also reported.
Dynamics of dense sheared granular flows. Part II. The relative velocity distributions

The distribution of relative velocities between colliding particles in shear flows of inelastic spheres is analysed in the volume fraction range 0.4–0.64. Particle interactions are considered to be due to instantaneous binary collisions, and the collision model has a normal coefficient of restitution en (negative of the ratio of the post- and pre-collisional relative velocities of the particles along the line joining the centres) and a tangential coefficient of restitution et (negative of the ratio of post- and pre-collisional velocities perpendicular to line joining the centres). The distribution of pre-collisional normal relative velocities (along the line joining the centres of the particles) is found to be an exponential distribution for particles with low normal coefficient of restitution in the range 0.6–0.7. This is in contrast to the Gaussian distribution for the normal relative velocity in an elastic fluid in the absence of shear. A composite distribution function, which consists of an exponential and a Gaussian component, is proposed to span the range of inelasticities considered here. In the case of rough particles, the relative velocity tangential to the surfaces at contact is also evaluated, and it is found to be close to a Gaussian distribution even for highly inelastic particles. Empirical relations are formulated for the relative velocity distribution. These are used to calculate the collisional contributions to the pressure, shear stress and the energy dissipation rate in a shear flow. The results of the calculation were found to be in quantitative agreement with simulation results, even for low coefficients of restitution for which the predictions obtained using the Enskog approximation are in error by an order of magnitude. The results are also applied to the flow down an inclined plane, to predict the angle of repose and the variation of the volume fraction with angle of inclination. These results are also found to be in quantitative agreement with previous simulations.
Gallium Arsenide and Gallium Nitride Semiconductors for Power and Optoelectronics Devices Applications

The advancement in technology in semiconductor materials significantly contributed in improvement of human life by bringing breakthrough in fabrication of optoelectronics and power devices which have wide applications in medicine and communication. The Gallium Arsenide (GaAs) and Gallium Nitride (GaN) are versatile materials for such applications but with relative merits and demerits. GaAs transistors are suitable for both narrowband and wideband applications due to very wide operating frequency range (30 MHz to millimetre-wave frequencies as high as 250 GHz). They are highly sensitive, generate very little internal noise and have power density typically around 1.5 W/mm. But low break down voltage (5x105V/cm), low output power (5-10W) and inability to withstand higher temperatures are the main limitations. On the other hand, GaN possess the improved physical and chemical characteristics, with high output power, high operating temperature (1000°C in vacuum), fast heat dissipation, high breakdown voltage (4x106V/cm), high power density (5-12W/mm), high frequency characteristics and large band gap (3.4eV) which allow significant reduction of devise size. Also high breakdown voltage increases the overall impedance which make it suitable in matching process and enables efficient operation in broad band region. The present paper critically analyses the GaAs and GaN semiconductors in relation to their significant physical and chemical properties, which make them suitable to make efficient power and optoelectronics devices for applications in communication, space and medicine.
Study of Chromatic Dispersion in Single-Mode Optical Fiber

In the optical communication system, optical fibers are used to transmit information in a long-haul communication system at a very high speed. However, attenuation causes loss in signal transmission. Chromatic dispersion is an ultimate limiting factor for attenuation in high-speed long-distance communication. The chromatic dispersion causes a broadening of the incident pulse while traversing along the fiber length. This broadening reduces the information-carrying capacity of the transmitted signal. Chromatic dispersion is caused by material and waveguide dispersion. We used COMSOL Multiphysics to evaluate chromatic dispersion for the different refractive indexes of silica glass by varying wavelengths from 1300 (nm) to 1600 (nm). We have modelled a 2D optical fiber using the Electromagnetic Wave, Frequency Domain. The effective mode index was computed using Mode Analysis and total dispersion is calculated theoretically. The computed values of chromatic dispersion are within 7% of theoretical values.
Investigation of the water desorption from components newly installed in a dry gas distribution system

Moisture in industrial gas affects the quality of products, and thus, studies on the water desorption behaviours of the components are necessary for industries to keep their gas distribution system extremely dry. In this study, the water desorption characteristics of a gas filter was evaluated, when it was newly installed in a setup operating in the trace-moisture regime. The desorption kinetics of the water based on the Arrhenius equation was utilized for analysing the experimental observations. The characteristics of water desorption from the filter were examined under a dried N2 gas flow with varying environmental conditions, such as temperature, pressure, flow rate and preconditioning relative humidity. For practical applications, a drying time of the filter, taken until the water vapour fraction reaches a target concentration (10 nmol·mol−1), was measured under varying conditions. Finally, the uncertainty budget on the drying time was evaluated. The findings of this study provide a practical insight on the water desorption behaviour, which would be useful for maintaining dry gas supply lines.
The role of gene regulation in redundant and synergistic information transfers in coherent feed-forward loop

For the ubiquitous coherent type-1 feed-forward loop (C1-FFL) motif, the master and co-regulators act as sources of information in decoding the output gene expression state. Using the variance-based definition of information within a Gaussian framework at steady state, we apply the partial information decomposition technique to quantify the redundant (common) and synergistic (complementary) information transfers to the output gene. By enabling the generic C1-FFL motif with complementarily tunable regulatory pathways and fixed gene product abundances, we examine the role of output gene regulation in maintaining the flow of these two multivariate information flavors. We find that the redundant and synergistic information transfers are simultaneously maximized when the direct and indirect output regulatory strengths are nearly balanced. All other manifestations of the generic C1-FFL motif, including the two terminal ones, namely, the two-step cascade and fan-out, transduce lesser amounts of these two types of information. This optimal decoding of the output gene expression state by a nearly balanced C1-FFL motif holds true in an extended repertoire of biologically relevant parametric situations. These realizations involve additional layers of regulation through changing gene product abundances, activation coefficients, and degradation rates. Our analyses underline the regulatory mechanisms through which the C1-FFL motif is able to optimally reduce its output uncertainty concurrently via redundant and synergistic modes of information transfer. We find that these information transfers are guided by fluctuations in the motif. The prevalence of redundancy over synergy in all regulatory implementations is also noteworthy.
Surface effects on thermoelectric properties of metallic and semiconducting nanowires

Metallic and semiconducting nanowires (NWs) are of interest in the field of thermoelectrics, because they act as model system to investigate the influence of surfaces on the thermoelectric transport properties. In single crystalline NWs, the grain boundary scattering is negligible and the surface‐to‐volume‐ratio is high. We present state‐of‐the‐art of the combination of the structural, chemical, and temperature‐dependent full thermoelectric characterization for individual single crystalline NWs, which is essential to conclude on surface effects. Temperature‐dependent measurements allow further conclusions on the scattering mechanisms. Simulations by the finite element method are performed on indented NWs to interpret the measurement results.
Association of digoxin with mortality and rehospitalization in heart failure patients treated with beta-blockers: Results from the Persian Heart Failure Patient Registry

BACKGROUND Numerous clinical trials have reported conflicting results regarding the benefit of digoxin in treating heart failure (HF) patients. This study was conducted with the aim to demonstrate the impact of added digoxin to beta-blocker and beta-blocker alone on all-cause mortality and rehospitalization among these patients. METHODS We investigated the data of 1998 patients admitted with a primary diagnosis of decompensated HF in the prospective Persian Heart Failure Patients Registry in Iran. The outcomes of interest were time until death and time until first rehospitalization. Multivariate cox regression was used to compare the impact of beta-blocker plus digoxin and beta-blocker alone on 2.5-year survival and 90-day rehospitalization. RESULTS The mean age of the participants was 69.18 ± 13.26 years, and 38.1% of patients were women. The incidence rate of all-cause mortality in the total sample was 0.18 and 0.22 in patients on beta-blocker plus digoxin and beta-blocker alone, respectively [incidence rate ratio (IRR) = 1.25; 95% CI: 0.92-1.7]. The adjusted risk of all-cause mortality was significantly higher in women discharged with beta-blocker plus digoxin than beta-blocker groups [hazard ratio (HR) = 2.31; 95% CI: 1.27-4.19]. Rates of 90-day first rehospitalization were 0.10 and 0.12 in the beta-blocker plus digoxin and beta-blocker alone groups, respectively (IRR = 0.85; 95% CI: 0.53-1.35). After adjustment for covariates, beta-blocker plus digoxin therapy had no significant effect on increasing the risk of 90-day first rehospitalization in the total cohort (HR = 0.77; 95% CI: 0.48-1.23), in men (HR = 0.73; 95% CI: 0.40-1.35), and women (HR = 0.76; 95% CI: 0.36-1.65). CONCLUSION In patients hospitalized with decompensated HF, digoxin administration at discharge was associated with increased 30-month mortality risk in women.
Submesoscale baroclinic instability in the balance equations

Abstract Ocean submesoscale baroclinic instability is studied in the framework of the balance equations. These equations are an intermediate model that includes balanced ageostrophic effects with higher accuracy than the quasigeostrophic approximation, but rules out unbalanced wave motions. As such, the balance equations are particularly suited to the study of baroclinic instability in submesoscale ocean dynamics. The linear baroclinic instability problem is developed in generality and then specialized to the case of constant vertical shear. It is found that non-quasigeostrophic effects appear only for perturbations with cross-front variation, and that perturbation energy can be generated through both baroclinic production and shear production. The Eady problem is solved analytically in the balance equation framework. Ageostrophic effects are shown to increase the range of unstable modes and the growth rate of the instability for perturbations with cross-front variation. The increased level of instability is attributed to both ageostrophic baroclinic production and shear production of perturbation energy; these results are verified in the primitive equations. Finally, submesoscale baroclinic instability is examined in a case where the buoyancy frequency increases rapidly near the bottom boundary, mimicking the increase of stratification at the base of the oceanic mixed layer. The qualitative results of the Eady problem are repeated in this case, with increased growth rates attributed to the production of perturbation energy by the ageostrophic velocity. The results show that submesoscale baroclinic instability acts to reduce lateral buoyancy gradients and their associated geostrophic shear simultaneously through lateral buoyancy fluxes and vertical momentum fluxes.