Variations in the Measured Carrier Lifetimes of n- 4H-SiC Epilayers

2008 ◽  
Vol 600-603 ◽  
pp. 489-492
Author(s):  
Paul B. Klein ◽  
Joshua D. Caldwell ◽  
Amitesh Shrivastava ◽  
Tangali S. Sudarshan
Keyword(s):  
Measurement Technique ◽  
Reasonable Agreement ◽  
Optical Measurement ◽  
Measurement Techniques ◽  
Carrier Dynamics ◽  
Injection Level ◽  
Carrier Lifetimes ◽  
Dynamics Simulations ◽  
Recombination Kinetics ◽  
Insight Into

The effects of measurement technique and measurement conditions (injection level, temperature) on the measured carrier lifetimes in n- 4H-SiC epilayers are investigated. For three optical measurement techniques, it is shown that the high and low injection lifetimes can vary dramatically. Differences in the lifetime for varying injection level and temperature are approached both experimentally and via carrier dynamics simulations, assuming Z1/Z2 as the dominant defect. Reasonable agreement between measured and calculated behavior is obtained, as is insight into the recombination kinetics associated with the lifetime limiting defect.

Timber screw connection: Study of the strain along the interface using optical measurement techniques and simulations

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 3859-3873
Author(s):  
Cedou Kumpenza ◽  
Andreas Ringhofer ◽  
Thomas Krenke ◽  
Adeayo Sotayo ◽  
Maximilian Pramreiter ◽  
...  
Keyword(s):  
Measurement Technique ◽  
Optical Measurement ◽  
Speckle Pattern ◽  
Measurement Techniques ◽  
Axial Loading ◽  
Electronic Speckle Pattern Interferometry ◽  
Pull Out ◽  
Grain Orientations ◽  
Thread Length ◽  
D 12

In various engineering applications, self-tapping screws are used to connect timber members. To describe their load-deformation relationship, a better understanding of the strain along the mechanical interface (i.e., timber-screw interface) is required. With a focus on the axial loading of self-tapping screws, only a few studies have dealt with the determination of the strain based on optical measurement techniques. Therefore, in the present study, the strain distribution at the timber-screw interface was monitored during pull-out tests using an optical measurement technique, called electronic speckle pattern interferometry (ESPI). Strains obtained from the ESPI measurements were compared with the results obtained from structural simulations conducted with finite element modelling (FEM). Three different types of solid spruce wood (Picea abies (L.) Karst.) specimens with different grain orientations connected with self-tapping screws (thread length lg = 130 mm, outer thread diameter d = 12 mm) were tested in withdrawal. There was a good agreement between the ESPI and FEM results, confirming that ESPI was a suitable measurement technique. The study also provided insights and results regarding the region of strain concentrations across the length of self-tapping screws.

Molecular Dynamics Simulations of the Glass Transition Temperature of Amorphous Cellulose

2012 ◽  
Vol 214 ◽  
pp. 7-11 ◽  
Author(s):  
Xiu Mei Zhang ◽  
M.A. Tschopp ◽  
Sheldon Q. Shi ◽  
Jun Cao
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Specific Volume ◽  
Reasonable Agreement ◽  
Reactive Force ◽  
Time Step ◽  
Amorphous Cellulose ◽  
Dynamics Simulations ◽  
Insight Into

Molecular modeling and dynamics simulations were used to generate equation of state properties of amorphous cellulose with the reactive force field ReaxFF which has been extensively parameterized and validated for hydrocarbon in a previous communication. Obtaining specific volume as a function of temperature for amorphous cellulose, the change in slope of the specific volume vs. temperature curves can be used to locate glass transition temperatures (Tg) reliably. With the results, there was reasonable agreement between experimental results and values of density and Tg obtained from the simulations. In addition, the suitable ReaxFF time step was investigated to help conserve the total energy of the system. The results show that the glass transition temperature can be used to verify the equilibration of the amorphous cellulose and to provide insight into the further deformation simulations.

An Optical Tool for Measuring Vortex-Induced Vibrations of Long Flexible Cylinders

2012 ◽  
Author(s):  
Francisco J. Huera-Huarte
Keyword(s):  
Wind Tunnel ◽  
Measurement Technique ◽  
Measurement System ◽  
Optical Measurement ◽  
Measurement Techniques ◽  
Flexible Cylinder ◽  
Response Measurement ◽  
Optical Measurement System ◽  
Vortex Induced Vibrations ◽  
And Performance

We describe the design and performance of a novel optical measurement system that can be used for measuring vortex-induced vibrations (VIV) of long flexible cylinders. We believe this is the first time this technology has been used to measure VIV in a long flexible cylinder. The emphasis is given to the measurement technique itself. It can be used either in air or in water and we believe it is a better alternative to other traditional vibration response measurement techniques used to study VIV in the laboratory. The measurement system is based on the Defocusing Digital Image Particle Velocimetry (DDPIV) concept, proposed by Willert and Gharib in [1] for measuring velocity flow fields. A set-up, which was built to conduct vortex-induced vibration measurements in a wind tunnel facility with a cross-section of 1.8 × 1.2 m, has been used in a laboratory to demonstrate the capabilities of the optical measurement system when known displacements are produced in the mappable or measurement volume. The same supporting structure designed to provide suport for the cylinder models inside the wind tunnel test section, has been used to hold a target which has been move to different known locations to measure the performance of the system. The design, description and performance of the measurement technique are discussed.

scholarly journals Insight into the origin of SARS-CoV-2 through structural analysis of receptor recognition: a molecular simulation study

RSC Advances ◽  
2021 ◽  
Vol 11 (15) ◽  
pp. 8718-8729
Author(s):  
Jixue Sun ◽  
Meijiang Liu ◽  
Na Yang
Keyword(s):  
Molecular Dynamics ◽  
Structural Analysis ◽  
Molecular Dynamics Simulations ◽  
Molecular Simulation ◽  
Simulation Study ◽  
Receptor Recognition ◽  
Dynamics Simulations ◽  
Insight Into

The origin of SARS-CoV-2 through structural analysis of receptor recognition was investigated by molecular dynamics simulations.

scholarly journals Computational Design of Radical Recognition Assay with the Possible Application of Cyclopropyl Vinyl Sulfides as Tunable Sensors

2021 ◽  
Vol 22 (14) ◽  
pp. 7637
Author(s):  
Liliya T. Sahharova ◽  
Evgeniy G. Gordeev ◽  
Dmitry B. Eremin ◽  
Valentine P. Ananikov
Keyword(s):  
Uv Light ◽  
Computational Design ◽  
Energy Profiles ◽  
Vinyl Sulfides ◽  
Tunable Sensors ◽  
Radical Generation ◽  
Metal Catalyzed ◽  
Dynamics Simulations ◽  
Simulations And Modeling ◽  
Insight Into

The processes involving the capture of free radicals were explored by performing DFT molecular dynamics simulations and modeling of reaction energy profiles. We describe the idea of a radical recognition assay, where not only the presence of a radical but also the nature/reactivity of a radical may be assessed. The idea is to utilize a set of radical-sensitive molecules as tunable sensors, followed by insight into the studied radical species based on the observed reactivity/selectivity. We utilize this approach for selective recognition of common radicals—alkyl, phenyl, and iodine. By matching quantum chemical calculations with experimental data, we show that components of a system react differently with the studied radicals. Possible radical generation processes were studied involving model reactions under UV light and metal-catalyzed conditions.

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