Figure Of Merit Approach Research Articles

P191 - Cardiac angiographic protocols: a figure of merit approach

P191 - Cardiac angiographic protocols: a figure of merit approach

Evaluating electrolyte additives for lithium-ion cells: A new Figure of Merit approach

Electrolyte additives are known to improve the performance of lithium-ion cells. In this work we examine the performance of Li1.03Ni0.5Mn0.3Co0.3O2-graphite (NMC532/Gr) cells containing combinations of lithium bis(oxalate)borate (LiBOB), vinylene carbonate (VC), trivinylcyclotriboroxane (tVCBO), prop-1-ene-1,3-sultone (PES), phenyl boronic acid ethylene glycol ester (PBE), tris(trimethylsilyl) phosphite (TMSPi), triethyl phosphite (TEPi), and lithium difluoro(oxalate)borate (LiDFOB) added to our baseline (1.2 M LiPF6 in EC:EMC, 3:7 w/w) electrolyte. In order to rank performance of the various electrolytes, we developed two separate figures of merit (FOM), which are based on the energy retention and power retention of the cells. Using these two metrics in conjunction, we show that only one of the fifteen electrolyte formulations tested significantly outperforms the baseline electrolyte: this electrolyte contains the 0.25 wt% tVCBO + 1 wt% TMSPi additive mix. Little correlation was observed between the FOMs for energy retention and power retention, which indicates that the mechanisms that govern these performance parameters are likely independent of each other. Our FOM approach has general applicability and can be used to develop electrolyte and electrode formulations that prolong the life of lithium-ion batteries.

A 700-V Device in High-Voltage Power ICs With Low On-State Resistance and Enhanced SOA

This paper presents a 700-V high-voltage laterally diffused metal-oxide-semiconductor (LDMOS) field-effect transistor with a p-body_Extension reduce surface field (RESURF) structure. Experimental results demonstrate that the low ON resistance and breakdown voltage (BV)- RON,sp figure of merit approach the ideal Baliga's power law, in addition, breaks the quasi-saturation limitation with enhanced device safe operating area (SOA). The optimal charge balance and geometrical design to achieve the lowest specific ON resistance (RON,sp) with the desired maximum high BV are displayed and discussed by simulations and experimental results. The 2-D simulations confirmed that, compared with conventional triple-RESURF structures, the presented device provides a fourfold reduction in the surface electric field on the source side and a 32% improvement in blocking voltage. The specific ON resistance demonstrates superior 40% lower performance than published Junction Isolation LDMOS device families. In addition, its twofold increase in SOA extension can improve the performance of circuit designs for switching power supply applications.

Figures of merit and constraints from testing general relativity using the latest cosmological data sets including refined COSMOS 3D weak lensing

We use cosmological constraints from current data sets and a figure of merit (FoM) approach to probe any deviations from general relativity (GR) at cosmological scales. The FoM approach is used to study the constraining power of various combinations of data sets on modified gravity (MG) parameters. We use recently refined HST-COSMOS weak-lensing tomography data, ISW-galaxy cross correlations from 2MASS and SDSS LRG surveys, matter power spectrum from SDSS-DR7 (MPK), WMAP7 temperature and polarization spectra, BAO from 2DF and SDSS-DR7, and Union2 compilation of supernovae, in addition to other bounds from H_0 measurements and BBN. We use 3 parametrizations of MG parameters that enter the perturbed field equations. In order to allow for variations with redshift and scale, the first 2 parametrizations use recently suggested functional forms while the third is based on binning methods. Using the first parametrization, we find that CMB + ISW + WL provides the strongest constraints on MG parameters followed by CMB+WL or CMB+MPK+ISW. Using the second parametrization or binning methods, CMB+MPK+ISW consistently provides some of the strongest constraints. This shows that the constraints are parametrization dependent. We find that adding up current data sets does not improve consistently uncertainties on MG parameters due to tensions between best-fit MG parameters preferred by different data sets. Furthermore, some functional forms imposed by the parametrizations can lead to an exacerbation of these tensions. Next, unlike some studies that used the CFHTLS lensing data, we do not find any deviation from GR using the refined HST-COSMOS data, confirming previous claims in those studies that their result may have been due to some systematic effect. Finally, we find in all cases that the values corresponding to GR are within the 95% confidence level contours for all data set combinations. (abridged)

Optical transparency and electrical conductivity of nonstoichiometric ultrathin InxOy films

The effect of thickness and composition on the electrical conductivity and optical transparency, mainly in the infrared, of ultrathin InxOy films was studied. InxOy films 35–470 Å thick with oxygen atomic fractions of ∼0.3 and ∼0.5 were prepared via dc magnetron sputtering. All films were polycrystalline, consisting of only the cubic bixbiyte phase of In2O3. The average grain size of the films increased from 30 to 95 nm as the film thickness increased. The weak dependence of the electrical conductivity on the frequency and the low activation energies for conduction, a few hundredths of an eV, provided an indication that free band conduction was the primary electrical conduction mechanism in the case of all ultrathin InxOy films. It was found that introducing a high degree of nonstoichiometry in the form of oxygen deficiency did not help improve the electrical conductivity, since not all vacancies contributed two free electrons for conduction and due to impurity scattering. The optical nature of these films, studied mainly by ellipsometry, was found to be dependent on the film’s composition and thickness. In the infrared, the dielectric function of all InxOy films was consistent with the Drude model, inferring that the transparency loss in this region was a result of free charge carriers. In the visible however, InxOy films under 170 Å, which had an oxygen atomic fraction of ∼0.5, were modeled by extending the Drude model to the shorter wavelengths. Films over 170 Å, with the same composition, were modeled using the Cauchy dispersion model, meaning that no absorption was measured. These results indicate that, optically, under specific compositions, ultrathin InxOy films undergo a transition from metalliclike behavior to dielectric behavior with increasing film thickness. Using a figure of merit approach, it was determined that a nonstoichiometric 230 Å thick InxOy film, with an oxygen atomic fraction of ∼0.3, had the best combination of conductivity and transparency, namely, absorption of less than 20% in the infrared, about 10% in the visible, and electrical resistance of only 230 Ω at 20 kHz. Such a film may be classified as a highly conductive transparent oxide even in the infrared.

Equivalent phantom sizes and shapes for brachytherapy dosimetric studies of and

The impact of phantom size and shape in brachytherapy dosimetry was assessed using Monte Carlo methods in liquid water for and point sources. This is needed since differences in published dosimetry data, both measurements and simulations, employ a variety of phantom sizes and shapes which can cause dose differences exceeding 30% near the phantom periphery. Spheres of radius, , were examined to determine the equivalent spherical phantom size to a variety of cylinder and cube sizes, and , respectively. These sizes ranged from . The equivalent for a given size cylinder or cube was determined using a figure of merit (FOM) function to minimize differences between radial dose functions, . Using the FOM approach, a linear fit was obtained for the equivalent for a given size cylinder or cube. The equivalent phantom for a cylinder, of diameter and length , is a sphere of in radius and the equivalent phantom for a cube of on each side is a sphere of 17.5 in radius. When normalizing all results to for comparisons of phantom shape, the absolute dose rates were equivalent within 0.1% for for both and . Correlation factors to permit comparisons of unbounded data for in 20 published datasets resulted in agreement generally within 2%. Residual differences with four datasets were attributed to methodological uncertainties in the published references.

Rate predictions for single-event effects - critique II

The concept of charge efficacy is introduced as a measure of the effectiveness of incident charge for producing single-event upsets. Efficacy is a measure of the single-event upset (SEU) sensitivity within a cell. It is illustrated how the efficacy curve can be determined from standard heavy-ion or pulsed laser SEU cross-section data, and discussed how it can be calculated from combined charge collection and circuit analysis. Upset rates can be determined using the figure of merit approach, and values determined from the laser cross-sections or from the mixed-mode simulations. The standard integral rectangular parallel-piped (IRPP) method for upset rate calculation is re-examined assuming that the probability of upset depends on the location of the hit on the surface. It is concluded that it is unnecessary to reformulate the IRPP approach.