AN EXPONENTIAL FITTING SCHEME FOR THE ELECTROTHERMAL DEVICE EQUATIONS SPECIFICALLY FOR THE SIMULATION OF AVALANCHE GENERATION

1993 ◽  
Vol 12 (2) ◽  
pp. 95-111 ◽  
Author(s):  
J.H.M. TEN THIJE BOONKKAMP ◽  
W.H.A. SCHILDERS
Keyword(s):  
Exponential Fitting ◽  
Avalanche Generation

A Discretization Scheme for a Quasi-Hydrodynamic Semiconductor Model

1997 ◽  
Vol 07 (07) ◽  
pp. 935-955 ◽  
Author(s):  
Ansgar Jüngel ◽  
Paola Pietra
Keyword(s):  
Finite Elements ◽  
Mixed Finite Elements ◽  
Exponential Fitting ◽  
Discretization Scheme ◽  
Drift Diffusion Model ◽  
Drift Diffusion ◽  
Current Conservation ◽  
Numerical Tests ◽  
Finite Elements Methods ◽  
Degenerate Type

A discretization scheme based on exponential fitting mixed finite elements is developed for the quasi-hydrodynamic (or nonlinear drift–diffusion) model for semiconductors. The diffusion terms are nonlinear and of degenerate type. The presented two-dimensional scheme maintains the good features already shown by the mixed finite elements methods in the discretization of the standard isothermal drift–diffusion equations (mainly, current conservation and good approximation of sharp shapes). Moreover, it deals with the possible formation of vacuum sets. Several numerical tests show the robustness of the method and illustrate the most important novelties of the model.

Assessment of Internal Damping in Uniaxially Stressed Metals: Exponential and Autoregressive Methods

1998 ◽  
Vol 120 (2) ◽  
pp. 177-184 ◽  
Author(s):  
A. L. Audenino ◽  
E. M. Zanetti ◽  
P. M. Calderale
Keyword(s):  
Nonlinear Behavior ◽  
Least Square ◽  
Dissipated Energy ◽  
Exponential Fitting ◽  
Damping Capacity ◽  
Test Machine ◽  
Internal Damping ◽  
Cast Irons ◽  
Decay Signal ◽  
Specific Damping Capacity

When a metallic material is highly stressed, its internal specific damping capacity increases showing a nonlinear behavior. In spite of this, the most part of experimental methods employ nonhomogeneous stress fields measuring only a volumetric average, often called structural damping. To overcome this problem the procedure herein presented extends the applicability of the plain traction or compression methods to higher frequency range (up to 300 Hz). The introduced methodology corrects for elastic energy and dissipated energy relative to the test machine and to the fixtures. The experimental procedure is based on the acquisition of a decay signal when the test machine excitation force has been removed. Two different methods to extract the pattern of internal damping versus material strain have been compared: one is based on least square exponential fitting while the other employs an autoregressive model. Best results have been obtained combining the two techniques taking into account also the variation of Young’s modulus with strain. The resulting curves of the loss factor as a function of strain amplitude for three steels and two cast irons are presented.

scholarly journals EFFECTS OF LINEAR AND EXPONENTIAL FITTING ON THE INITIAL RATE OF CHANGE IN CO2 CONCENTRATION ACROSS THE SOIL SURFACE

2007 ◽  
Vol 31 (3) ◽  
pp. 380-385
Author(s):  
WEN Xue-Fa ◽  
◽  
SUN Xiao-Min ◽  
LIU Yun-Fen ◽  
LI Xiao-Bo
Keyword(s):  
Initial Rate ◽  
Soil Surface ◽  
Rate Of Change ◽  
Exponential Fitting

scholarly journals Variation of female pronucleus reveal oocyte or embryo abnormality: An expert experience deep learning of non-dark box analysis

2021 ◽  
Author(s):  
Jingwei Yang ◽  
Yikang Wang ◽  
Chong Li ◽  
Wei Han ◽  
Weiwei Liu ◽  
...  
Keyword(s):  
Deep Learning ◽  
Measurement Method ◽  
Genetic Test ◽  
Automatic Recognition ◽  
Exponential Fitting ◽  
Qualitative Detection ◽  
Female Pronucleus ◽  
Analysis Of The Images ◽  
Zygote Stage ◽  
Paradoxical Results

Background: Pronuclear assessment appears to have the ability to distinguish good and bad embryos in the zygote stage,but paradoxical results were obtained in clinical studies.This situation might be caused by the robust qualitative detection of the development of dynamic pronuclei. Here,we aim to establish a quantitative pronuclear measurement method by applying expert experience deep learning from large annotated datasets. Methods: Convinced handle-annotated 2PN images(13419) were used for deep learning then corresponded errors were recorded through handle check for subsequent parameters adjusting. We used 790 embryos with 52479 PN images from 155 patients for analysis the area of pronuclei and the preimplantation genetic test results.Establishment of the exponential fitting equation and the key coefficient β1 was extracted from the model for quantitative analysis for pronuclear(PN) annotation and automatic recognition. Findings: Based on the female original PN coefficient β1,the chromosome normal rate in the blastocyst with biggest PN area is much higher than that of the blastocyst with smallest PN area(58.06% vs.45.16%, OR=1.68[1.07-2.64];P=0.031).After adjusting coefficient β1 by the first three frames which high variance of outlier PN areas was removed, coefficient β1 at 12 hours and at 14 hours post-insemination,similar but stronger evidence was obtained. All these discrepancies resulted from the female propositus in the PGT(SR) subgroup and smaller chromosomal errors. Conclusion(s): The results suggest that detailed analysis of the images of embryos could improve our understanding of developmental biology. Funding: None

scholarly journals Damping Measurements in Tube Bundles Subjected to Two-Phase Cross Flow

2006 ◽  
Author(s):  
Joaquin E. Moran ◽  
David S. Weaver
Keyword(s):  
Flow Regime ◽  
Void Fraction ◽  
Mass Flux ◽  
Damping Ratio ◽  
Logarithmic Decrement ◽  
Working Fluid ◽  
Exponential Fitting ◽  
Two Phase ◽  
Tube Bundles ◽  
Half Power

An experimental study was conducted to investigate two-phase damping in tube arrays. The objective was to compare different measurement methodologies in order to obtain a more reliable damping estimate. This will allow for improved guidelines related to failures due to fluidelastic instability in tube bundles. The methods compared were the traditionally used half-power bandwidth, the logarithmic decrement and an exponential fitting to the tube decay response. The working fluid used was Refrigerant 11 (Freon), which better models the real steam-water problem, as it allows for phase change. The void fraction was measured using a gamma densitometer, introducing an improvement over the traditional Homogeneous Equilibrium Model (HEM) in terms of velocity and density predictions. The results obtained by using the half-power bandwidth method agree with data previously reported for two-phase flow. The experiments showed that the half-power bandwidth produces higher damping values than the other two, but only up to a certain void fraction. After that point, the results obtained from the three methods are very similar. The exponential fitting proved to be more consistent than the logarithmic decrement, and it is not as sensitive as the half-power bandwidth to the frequency shifting caused by the change in added mass around the tube. By plotting the damping ratio as a function of void fraction, pitch mass flux and flow regime, we were able to verify that damping is more dependent on void fraction and flow regime than on mass flux.

scholarly journals Weights of the exponential fitting multistep algorithms for first-order ODEs

2001 ◽  
Vol 132 (1) ◽  
pp. 83-93 ◽  
Author(s):  
L.Gr. Ixaru ◽  
M. Rizea ◽  
G.Vanden Berghe ◽  
H.De Meyer
Keyword(s):  
Exponential Fitting ◽  
First Order
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