Gaussian Width Research Articles

Gray and Dark Soliton Behavior and Population Under a Symmetric and Asymmetric Potential Trap

We numerically study the impact of Gaussian barrier height and width on the gray solitons population in a symmetric and asymmetric potential trap. The gray solitons are created in a double-well potential by the density engineering method. Two identical Bose-Einstein condensate fragments are confined and made to collide by switching off the Gaussian barrier in a double-well potential. We find that the gray solitons population can be manipulated by Gaussian barrier height and width. We also study the gray solitons population dependence on the coupling strength. Moreover, we also study the impact of an asymmetry present in the double-well potential. We observe that such an asymmetry always swings the point of collision of the gray solitons. Later, a stationary dark soliton is created by the phase imprinting method and we observe that the initial asymmetry in the double-well potential trap sets the dark soliton into oscillation.

Machine learning for automated quality assurance in radiotherapy: A proof of principle using EPID data description.

Developing automated methods to identify task-driven quality assurance (QA) procedures is key toward increasing safety, efficacy, and efficiency. We investigate the use of machine learning (ML) methods for possible visualization, automation, and targeting of QA, and assess its performance using multi-institutional data. To enable automated analysis of QA data given its higher dimensional nature, we used nonlinear kernel mapping with support vector data description (SVDD) driven approaches. Instead of using labeled data as in typical support vector machine (SVM) applications, which requires exhaustive annotation, we applied a clustering extension of SVDD, which identifies the minimal enclosing hypersphere in the feature space defined by a kernel function separating normal operations from possible failures (i.e., outliers). In our case, QA test data are mapped by a Gaussian kernel to a higher dimensional feature space and then the minimal enclosing sphere was identified. This sphere, when mapped back to the input data space along the principal components, can separate the data into several components, each enclosing a separate cluster of QA points that could be used to evaluate tolerance boundaries and test reliability. We evaluated this approach for gantry sag, radiation field shift, and [multileaf collimator (MLC)] offset data acquired using electronic portal imaging devices (EPID), as representative examples. Data from eight LINACS and seven institutions (n=119) were collected. A standardized EPID image of a phantom with fiducials provided deviation estimates between the radiation field and phantom center at four cardinal gantry angles. Deviation measurements in the horizontal direction (0°, 180°) were used to determine the gantry sag and deviations in the vertical direction (90°, 270°) were used to determine the field shift. These measurements were fed into the SVDD clustering algorithm with varying hypersphere radii (Gaussian widths). For gantry sag analysis, two clusters were identified one of which contained 2.5% of the outliers and also exceeded the 1mm tolerance set by TG-142. In the case of field shifts, SVM clustering identified two distinct classes of measurements primarily driven by variations in the second principal component at 270°. Results from MLC analysis identified one outlier cluster (0.34%) along Leaf offset Constancy (LoC) axis that coincided with TG-142 limits. Machine learning methods based on SVDD clustering are promising for developing automated QA tools and providing insights into their reliability and reproducibility.

Investigation of Charge Trapping Induced by DCM–TPA Dopant in Organic Light Emitting Devices Composed of (NPB:Alq3):DCM–TPA Mixed Host-Doped Emitting Layer

In the first part of this manuscript, two OLED devices composed of Alq3:DCM–TPA organic material as doped emitting layer, have been simulated. In the first device, the reduced mobility property of this doped layer and in the second device, trapping effects of this dopant are considered. With comparison of the simulation results obtained for these devices, the approximated values of the traps concentration and Gaussian width of traps is obtained. In the second part, the OLED devices with considering of the NPB:Alq3 organic material as mixed host emitting layer have been simulated for obtaining optimal thickness of the emitting layer. In the final part, an OLED device composed of (NPB:Alq3):DCM–TPA organic material as mixed host-doped emitting layer has been simulated for studying the influence of DCM–TPA dopant on the performance of this device.

Minimization effect of sedimentary layer on synthetic receiver function

We calculated the radial synthetic model of receiver function consisting of the sedimentary layer, crust, and mantle (SCM). The models were computed using the program hrftn96 implemented in computer program in seismology (CPS). Synthetic receiver functions are generated using the following parameters: for sedimentary layers, Vp, Vs, and density are 1.8, 0.41 and 1.83 g/cm3 respectively; for the crustal layer, the values are 6.10, 3.52 and 2.73 g/cm3 with the depth of the Moho layer at 40 km; and for the mantle, the values are 8.15, 4.7 and 3.36 g/cm3. We varied sedimentary layer with the thickness of 0.0, 0.4, 0.5 and 1.0 km. We applied the Gaussian width parameter of 1.5 removing frequency content above 0.75 Hz. We designed the filter for the synthetic receiver function model in order to minimize reverberation effect due to the presence of sedimentary layer near the surface. To test the effectiveness of this filter, we adopted H-κ stacking method for this model to calculate the moho thickness before and after sediment removal.

Properties of the Diffuse Emission around Warm Loops in Solar Active Regions

Abstract Coronal loops in active regions are the subjects of intensive investigation, but the important diffuse unresolved emission in which they are embedded has received relatively little attention. Here I measure the densities and emission measure (EM) distributions of a sample of background–foreground regions surrounding warm (2 MK) coronal loops, and introduce two new aspects to the analysis. First, I infer the EM distributions only from temperatures that contribute to the same background emission. Second, I measure the background emission co-spatially with the loops so that the results are truly representative of the immediate loop environment. The second aspect also allows me to take advantage of the presence of embedded loops to infer information about the (unresolvable) magnetic field in the background. I find that about half of the regions in my sample have narrow but not quite isothermal EM distributions with a peak temperature of 1.4–2 MK. The other half have broad EM distributions (Gaussian width >3 × 105 K), and the width of the EM appears to be correlated with peak temperature. Densities in the diffuse background are log (n/cm−3) = 8.5–9.0. Significantly, these densities and temperatures imply that the co-spatial background is broadly compatible with static equilibrium theory (RTV scaling laws) provided that the unresolved field length is comparable to the embedded loop length. For this agreement to break down, the field length in most cases would have to be substantially longer than the loop length, a factor of 2–3 on average, which for the sample in this work approaches the dimensions of only the largest active regions.

Relationship between the line width of the atomic and molecular ISM in M33

ABSTRACT We investigate how the spectral properties of atomic (H i) and molecular (H2) gas, traced by CO(2−1) , are related in M33 on 80 pc scales. We find the H i and CO(2−1) velocity at peak intensity to be highly correlated, consistent with previous studies. By stacking spectra aligned to the velocity of H i peak intensity, we find that the CO line width (σHWHM = 4.6 ± 0.9 ${\rm km\, s^{-1}}$ ; σHWHM is the effective Gaussian width) is consistently smaller than the H i line width (σHWHM = 6.6 ± 0.1 ${\rm km\, s^{-1}}$), with a ratio of ∼0.7, in agreement with Druard et al. The ratio of the line widths remains less than unity when the data are smoothed to a coarser spatial resolution. In other nearby galaxies, this line width ratio is close to unity which has been used as evidence for a thick, diffuse molecular disc that is distinct from the thin molecular disc dominated by molecular clouds. The smaller line width ratio found here suggests that M33 has a marginal thick molecular disc. From modelling individual lines of sight, we recover a strong correlation between H i and CO line widths when only the H i located closest to the CO component is considered. The median line width ratio of the line-of-sight line widths is 0.56 ± 0.01. There is substantial scatter in the H i –CO(2−1) line width relation, larger than the uncertainties, that results from regional variations on <500 pc scales, and there is no significant trend in the line widths, or their ratios, with galactocentric radius. These regional line width variations may be a useful probe of changes in the local cloud environment or the evolutionary state of molecular clouds.

The Flared Gas Structure of the Transitional Disk around Sz 91

Abstract We report 0.″14 resolution observations of the dust continuum at band 7, and the CO(3–2) and HCO+(4–3) line emissions toward the transitional disk around Sz 91 with the Atacama Large Millimeter/submillimeter Array. The dust disk appears to be an axisymmetric ring, peaking at a radius of ∼95 au from a Gaussian fit. The Gaussian fit widths of the dust ring are 24.6 and 23.7 au for the major and the minor axes, respectively, indicating that the dust ring is not geometrically thin. The gas disk extends out to ∼320 au and is also detected in the inner hole of the dust ring. A twin-line pattern is found in the channel maps of CO, which can be interpreted as the emission from the front and rear of the flared gas disk. We perform radiative transfer calculations using RADMC-3D to check whether the twin-line pattern can be reproduced assuming that the flared gas disk has a power-law form for the column density and T gas = T dust. The thermal Monte Carlo calculation in RADMC-3D shows that the disk temperature has a gradient along the vertical direction beyond the dust ring, as it blocks the stellar radiation, and thus the twin-line pattern can be naturally explained by the flared gas disk in combination with the dust ring. In addition, no significant depletion of the CO molecules in the cold midplane achieves a reasonable agreement with the observed twin-line pattern. This result indicates that the CO emission from the rear surface must be heavily absorbed in the cold midplane.

Giant tunable Goos–Hänchen shifts based on surface plasmon resonance with Dirac semimetal films

Surface plasmon resonance (SPR) with bulk Dirac semimetals (BDS) has been proposed to enhance the Goos–Hänchen (GH) shift. It is found that a large positive and negative GH shift can be obtained by adjusting the thickness of the BDS film, and the GH shift is very sensitive to the Fermi level of the BDS film. By changing the Fermi level of the BDS film, we can get a controllable negative GH shift. The largest GH shift of the proposed configuration, as large as 361.4 times the incident wavelength, has been obtained. Compared with the traditional SPR structure, the GH shift is increased by nearly 13.4 times, which indicates that BDS is expected to replace the traditional SPR structure to excite the stronger SPR. Finally, the numerical simulation results further verify that the giant shift can be obtained by a finite width Gaussian beam in our proposed calculation. Based on this giant and controllable GH shift, it may have potential applications in tunable sensors, switches, filters, and other devices.

Generalizing CoSaMP to signals from a union of low dimensional linear subspaces

The idea that signals reside in a union of low dimensional subspaces subsumes many low dimensional models that have been used extensively in the recent decade in many fields and applications. Until recently, the vast majority of works have studied each one of these models on its own. However, a recent approach suggests providing general theory for low dimensional models using their Gaussian mean width, which serves as a measure for the intrinsic low dimensionality of the data. In this work we use this novel approach to study a generalized version of the popular compressive sampling matching pursuit (CoSaMP) algorithm, and to provide general recovery guarantees for signals from a union of low dimensional linear subspaces, under the assumption that the measurement matrix is Gaussian. We discuss the implications of our results for specific models, and use the generalized algorithm as an inspiration for a new greedy method for signal reconstruction in a combined sparse-synthesis and cosparse-analysis model. We perform experiments that demonstrate the usefulness of the proposed strategy.

Multiple Testing with the Structure-Adaptive Benjamini–Hochberg Algorithm

SummaryIn multiple-testing problems, where a large number of hypotheses are tested simultaneously, false discovery rate (FDR) control can be achieved with the well-known Benjamini–Hochberg procedure, which a(0, 1]dapts to the amount of signal in the data, under certain distributional assumptions. Many modifications of this procedure have been proposed to improve power in scenarios where the hypotheses are organized into groups or into a hierarchy, as well as other structured settings. Here we introduce the ‘structure-adaptive Benjamini–Hochberg algorithm’ (SABHA) as a generalization of these adaptive testing methods. The SABHA method incorporates prior information about any predetermined type of structure in the pattern of locations of the signals and nulls within the list of hypotheses, to reweight the p-values in a data-adaptive way. This raises the power by making more discoveries in regions where signals appear to be more common. Our main theoretical result proves that the SABHA method controls the FDR at a level that is at most slightly higher than the target FDR level, as long as the adaptive weights are constrained sufficiently so as not to overfit too much to the data—interestingly, the excess FDR can be related to the Rademacher complexity or Gaussian width of the class from which we choose our data-adaptive weights. We apply this general framework to various structured settings, including ordered, grouped and low total variation structures, and obtain the bounds on the FDR for each specific setting. We also examine the empirical performance of the SABHA method on functional magnetic resonance imaging activity data and on gene–drug response data, as well as on simulated data.

Gaussian Width Bounds with Applications to Arithmetic Progressions in Random Settings

Motivated by problems on random differences in Szemer\'{e}di's theorem and on large deviations for arithmetic progressions in random sets, we prove upper bounds on the Gaussian width of point sets that are formed by the image of the $n$-dimensional Boolean hypercube under a mapping $\psi:\mathbb{R}^n\to\mathbb{R}^k$, where each coordinate is a constant-degree multilinear polynomial with 0-1 coefficients. We show the following applications of our bounds. Let $[\mathbb{Z}/N\mathbb{Z}]_p$ be the random subset of $\mathbb{Z}/N\mathbb{Z}$ containing each element independently with probability $p$. $\bullet$ A set $D\subseteq \mathbb{Z}/N\mathbb{Z}$ is $\ell$-intersective if any dense subset of $\mathbb{Z}/N\mathbb{Z}$ contains a proper $(\ell+1)$-term arithmetic progression with common difference in $D$. Our main result implies that $[\mathbb{Z}/N\mathbb{Z}]_p$ is $\ell$-intersective with probability $1 - o(1)$ provided $p \geq \omega(N^{-\beta_\ell}\log N)$ for $\beta_\ell = (\lceil(\ell+1)/2\rceil)^{-1}$. This gives a polynomial improvement for all $\ell \ge 3$ of a previous bound due to Frantzikinakis, Lesigne and Wierdl, and reproves more directly the same improvement shown recently by the authors and Dvir. $\bullet$ Let $X_k$ be the number of $k$-term arithmetic progressions in $[\mathbb{Z}/N\mathbb{Z}]_p$ and consider the large deviation rate $\rho_k(\delta) = \log\Pr[X_k \geq (1+\delta)\mathbb{E}X_k]$. We give quadratic improvements of the best-known range of $p$ for which a highly precise estimate of $\rho_k(\delta)$ due to Bhattacharya, Ganguly, Shao and Zhao is valid for all odd $k \geq 5$. We also discuss connections with error correcting codes (locally decodable codes) and the Banach-space notion of type for injective tensor products of $\ell_p$-spaces.

Modified Gaussian Wave Packet Method for Calculating Initial State Wave Functions in Photodissociation.

A modified Gaussian wave packet relaxation method is proposed to calculate the ground state wave function using an expansion of frozen Gaussian wave packets. This new procedure consists of two steps. In the first step, a multidimensional Gaussian product placed at the ground state equilibrium geometry is propagated in imaginary time. The relaxation optimizes the widths of the one-dimensional Gaussians. In the second step, additional Gaussian wave packets with the same widths are placed near the equilibrium geometry, and the corresponding expansion coefficients are optimized using the same relaxation method. This new algorithm is tested in photodissociation of NOCl and NH3, and the results show good agreement with the exact results in the energy, wave function, and absorption spectrum. In particular, the highly structured absorption spectrum of NH3 is reproduced, underscoring the accuracy of both the initial wave packet and the excited state propagation.

Self-induced velocity correction for improved drag estimation in Euler–Lagrange point-particle simulations

In Euler–Lagrange (EL) simulations the force on each particle is obtained from a point-particle model, which is then coupled back to the fluid momentum. The feedback force modifies the flow at the particle location and it is important to evaluate the resulting self-induced velocity disturbance, since the point-particle models are based on the undisturbed flow. An exact solution of the Oseen's equation for flow generated by a steady Gaussian feedback force was obtained, which along with the corresponding finite Reynolds number numerical simulations, provided a steady model for the self-induced velocity disturbance. The unsteady problem of a time dependent Gaussian feedback force was then theoretically investigated in the zero Reynolds number limit. The corresponding finite Reynolds number unsteady results were obtained using companion numerical simulations. Based on these results an unsteady model for predicting the self-induced velocity disturbance was developed. The two main non-dimensional quantities affecting the self-induced velocity disturbance are the Reynolds number based on Gaussian width Reσ and the non-dimensional feedback force F˜. The resulting self-induced velocity correction model is general and can be applied in a variety of EL point-particle simulations, with the time history of Reσ and F˜ as input. The quasi-steady and unsteady versions of the model were tested in the context of a freely settling particle. The unsteady model was shown to predict the self-induced velocity disturbance to reasonable accuracy for a wide range of Reynolds and Stokes numbers. Issues pertaining to practical implementation and limitations are discussed.

RELICS: Strong Lensing Analysis of the Galaxy Clusters Abell S295, Abell 697, MACS J0025.4-1222, and MACS J0159.8-0849

Abstract We present a strong lensing analysis of four massive galaxy clusters imaged with the Hubble Space Telescope in the Reionization Lensing Cluster Survey. We use a light-traces-mass technique to uncover sets of multiple images and constrain the mass distribution of the clusters. These mass models are the first published for Abell S295 and MACS J0159.8-0849 and are improvements over previous models for Abell 697 and MACS J0025.4-1222. Our analysis for MACS J0025.4-1222 and Abell S295 shows a bimodal mass distribution supporting the merger scenarios proposed for these clusters. The updated model for MACS J0025.4-1222 suggests a substantially smaller critical area than previously estimated. For MACS J0159.8-0849 and Abell 697, we find a single peak and relatively regular morphology revealing fairly relaxed clusters. Despite being less prominent lenses, three of these clusters seem to have lensing strengths, i.e., cumulative area above certain magnification, similar to those of the Hubble Frontier Fields clusters (e.g., A(μ > 5) ∼ 1–3 arcmin2, A(μ > 10) ∼ 0.5–1.5 arcmin2), which in part can be attributed to their merging configurations. We make our lens models publicly available through the Mikulski Archive for Space Telescopes. Finally, using Gemini-N/GMOS spectroscopic observations, we detect a single emission line from a high-redshift J 125 ≃ 25.7 galaxy candidate lensed by Abell 697. While we cannot rule out a lower-redshift solution, we interpret the line as Lyα at z = 5.800 ± 0.001, in agreement with its photometric redshift and dropout nature. Within this scenario, we measure a Lyα rest-frame equivalent width of 52 ± 22 Å and an observed Gaussian width of 117 ± 15 km s−1.

Varying driver velocity fields in photospheric MHD wave simulations

Torsional motions are ubiquitous in the solar atmosphere. In this work, we perform 3D numerical simulations which mimic a vortex-type photospheric driver with a Gaussian spatial profile. This driver is implemented to excite MHD waves in an axially symmetric, 3D magnetic flux tube embedded in a realistic solar atmosphere. The Gaussian width of the driver is varied and the resulting perturbations are compared. Velocity vectors were decomposed into parallel, perpendicular and azimuthal components with respect to pre-defined magnetic flux surfaces. These components correspond broadly to the fast, slow and Alfven modes, respectively. From these velocities the corresponding wave energy fluxes are calculated, allowing us to estimate the contribution of each mode to the energy flux. For the narrowest driver ($0.15$ Mm) the parallel component accounts for $\sim 55 - 65\%$ of the flux. This contribution increases smoothly with driver width up to nearly $90\%$ for the widest driver ($0.35$ Mm). The relative importance of the perpendicular and azimuthal components decrease at similar rates. The azimuthal energy flux varied between $\sim 35\%$ for the narrowest driver and $< 10\%$ for the widest one. Similarly, the perpendicular flux was $\sim 25 - 10\%$. We also demonstrate that the fast mode corresponds to the sausage wave in our simulations. Our results therefore show that the fast sausage wave is easily excited by this driver and that it carries the majority of the energy transported. For this vortex-type driver the Alfven wave does not contribute a significant amount of energy.

(Invited) Elucidating the Micro Phase-Separation of Mixed Kappa and Iota Carrageenan Gels Using Multiple Particle Tracking

Carrageenan is a family of linear sulfated polysaccharides extracted from seaweeds. Among the different types of carrageenan, kappa carrageenan (KC) and iota carrageenan (IC) are widely used in industries due to its gelling behavior. Because of its importance in industries, KC and IC as well as its mixtures have been extensively studied using different methods. However, it is still unclear whether mixed KC:IC undergo a phase separated network structure of IC-rich and KC-rich or interpenetrated network structure. In this report, the network structure and gelation mechanism of KC, IC and its mixture were elucidated using multiple particle tracking. Sodium-type κ- and ι- carrageenan powder was purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan). All samples were dialyzed against NaCl solution and subsequently against deionized water, to obtain Na+ type carrageenan solutions. Samples were prepared by diluting carrageenan and KCl solutions and heated for 30 min at 70 °C under vigorous stirring. The prepared solutions were mixed using vortex to obtain 1.5% w/w carrageenan with 10 mM KCl and heated at 90 °C for 20 min. Fluorescently labelled 0.1 μm particles (Green, ThermoScientific) were added at a concentration of ~0.01% (v/w) at 90 °C and stirred for another 5 min to assure homogenous dispersion. Mixture of KC and IC was prepared at different volume fraction of IC. Movies of the diffusing particles were recorded at a frame rate of 7.5 frames per second for 110 seconds. In cooling experiments, particle tracking was performed at different sample temperatures from 50 °C to 10 °C. In storage experiments, hot solutions of carrageenan were cooled down from 50 °C to 5 °C at a rate of 1 °C/min in a temperature-controlled incubator to form a gel. The gelled sample was stored at 5 °C prior to experiment and particle tracking was performed at 5 °C. Particle tacking was implemented in Mathematica 10 (Wolfram Research, Inc., USA). The temperature dependence of the mean square displacement (MSD) of particles in KC, IC and mixed KC:IC gels were carried out to quantify the dynamics of the evolving network structure on cooling as shown in Figure 1. In mixed KC:IC, a two-step decrease in MSD was observed. The onset of the observed decrease is close to the decrease in pure KC and IC gels. This trend is consistent with the observed increase in the viscoelastic modulus in dynamic viscoelasticity measurements. The decrease in the MSD with decreasing temperature is due to the steric hindrance created by the formation of clusters of IC and KC chain aggregates. This suggests that KC and IC chains formed aggregates independently on cooling. In pure carrageenan, IC gels formed weak entanglement among clusters of IC chain that allowed diffusion of particles through crevices of the entangled clusters while KC gels rapidly formed thick aggregates of interconnected clusters that confined the particles. On the other hand, in mixed KC:IC, the presence of IC clusters decreased the mobility of KC chains at low temperature thus slowed the formation of stable clusters of KC. With storage time, a broad distribution of MSD was observed for the mixed gels. This suggests that an inhomogeneous solution was formed as KC and IC clusters continue to rearrange to form a stable network. The degree of heterogeneity in the mixed gels is reflected in the corresponding van Hove distribution of particle displacement and the distribution of MSD as a function of slope. In the van Hove distribution, a bimodal Gaussian form with a broad and narrow Gaussian width fit well on the distribution suggests a mobile and immobile fraction of particle at each mixing ratios. In the distribution of MSD as a function of slope, the mobile and immobile particles were identified and clustered accordingly. This suggests that the presence of mobile particles was due to the existence of IC-rich domains that allowed diffusion of particles and the immobile particles was due to the confinement of particles in KC-rich domains as shown in the graphical representation in Figure 1. This is consistent with the proposed gelation mechanism of a local phase separation into IC-rich and KC-rich domains. As the volume fraction of IC was increased, the number of mobile particles increased consequently and suggests a phase transition from a sea-island (80%KC:20%IC) to a bi-continuous (50%KC:50%IC) to an island-sea (30%KC:70%IC) network structure is likely to occur. Figure 1

Development of Total Decay Energy Spectrometry of α-Emitting Radionuclides Using Metallic Magnetic Calorimeters

Total decay energy spectrometry with cryogenic detectors is a promising technique for radionuclide analysis of α-emitting nuclides. The radioactive sample is embedded in the detector absorber, and the total decay energy for each disintegration is measured as a temperature elevation. We are developing this technique with metallic magnetic calorimeters (MMCs). The main condition of this technique is a detection efficiency close to unity. However, some α-emitting nuclides emit intense γ-rays that can partially escape from the absorber. So a feasibility study for several nuclides has been carried out based on Monte Carlo simulations of the detection efficiency and numerical calculations of the expected energy resolution to identify the radionuclides that can potentially be measured. Furthermore, an MMC prototype has been built and tested. The total decay energy spectrum of Po-210 was measured, and a FWHM energy resolution of 1.25 keV at 5.4 MeV was obtained and a Gaussian width at half maximum of 0.827 (5) keV. The baseline FWHM energy resolution is 207 eV, consistent with the resolution obtained on low-energy L X-rays in the same spectrum at 14 keV.

Injectable nanoemulsions prepared by high pressure homogenization: processing, sterilization, and size evolution

Oil-in-water nanoemulsions are promising colloidal dispersions for the delivery of hydrophobic drugs. The use of polysorbate 80 as stabilizing agent in these formulations can improve the delivery of the drug to the brain, thanks to a tropism for apolipoproteins. The aim of this study was to formulate injectable nanoemulsions stabilized by polysorbate 80, which meet United States Pharmacopoeia particle size requirements for parenteral emulsions. Nanoemulsions were prepared by high pressure homogenization and characterized in terms of mean hydrodynamic diameter, Gaussian distribution width, and volume-weighted percentage of fat droplets greater than 1.79 µm (PFAT1.79) or 5 µm (PFAT5). The effect of autoclaving, filtration and loading with nile red (a lipophilic fluorescent dye) on the nanoemulsions was evaluated. Real-time and accelerated stability tests were also performed. To satisfy Unites States Pharmacopoeia particle size specifications, nanoemulsions required six homogenization cycles. PFAT5 and PFAT1.79 were the particle size parameters more sensitive to discriminate the effect of homogenization, autoclaving, filtration and loading as well as globule size evolution during real-time stability tests. Results from accelerated stability studies correlated with the PFAT5 values measured over time. Overall, the study demonstrates that all nanoemulsions studied (autoclaved, filtered or loaded) satisfies United States Pharmacopoeia particle size requirements up to 90 days, maintaining PFAT5 to values lower than 0.05% v/v.

Spectral Distribution of Oscillator Strength for Core-to-Valence Transitions probed by using X-ray Absorption and Total Electron Yield Modes

Abstract Changes in spectral distribution of oscillator strength for core-to-valence transitions probed by X-ray absorption and total electron yield (TEY) modes are studied in more detail. The quantitative analysis of their redistribution in TEY due to the saturation effect is performed by applying the model M ˜ $\tilde M$ -function method suggested by Flesch et al. J. Chem. Phys. 138 (2013) 144302. The model M ˜ $\tilde M$ -function method is generalized to account for the saturation-induced distortion of the line shape of the transitions embedded into the core ionization continua and located below them. It is shown that TEY measurements produce essential changes not only in the relative intensity of the transitions but also shift upward the transition energy, broaden the Lorentzian and Gaussian widths and enhance the line asymmetry. The Gaussian width of the TEY signal undergoes the most substantial broadening though the Lorentzian width increases significantly too. The saturation-induced distortion of the line shapes is not negligible even if the well-known escape-to-penetration condition is valid.

Experimental Results and Numerical Simulation of the Target RCS using Gaussian Beam Summation Method

This paper presents a numerical and experimental study of Radar Cross Section (RCS) of radar targets using Gaussian Beam Summation (GBS) method. The purpose GBS method has several advantages over ray method, mainly on the caustic problem. To evaluate the performance of the chosen method, we started the analysis of the RCS using Gaussian Beam Summation (GBS) and Gaussian Beam Launching (GBL), the asymptotic models Physical Optic (PO), Geometrical Theory of Diffraction (GTD) and the rigorous Method of Moment (MoM). Then, we showed the experimental validation of the numerical results using experimental measurements which have been executed in the anechoic chamber of Lab-STICC at ENSTA Bretagne. The numerical and experimental results of the RCS are studied and given as a function of various parameters: polarization type, target size, Gaussian beams number and Gaussian beams width.