scholarly journals Ultra-low thermal conductivity and acoustic dynamics of Si nanostructured metalattices probed using ultrafast high harmonic beams

2019 ◽  
Vol 205 ◽  
pp. 04006
Author(s):  
Begoña Abad ◽  
Travis Frazer ◽  
Joshua Knobloch ◽  
Jorge Hernández-Charpak ◽  
Hiu Cheng ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Acoustic Wave ◽  
Thermal Transport ◽  
Extreme Ultraviolet ◽  
High Harmonic ◽  
Wave Dispersion ◽  
Acoustic Wave Propagation ◽  
High Quality ◽  
Very High ◽  
Good Agreement

We extend optical nanometrology capabilities to smaller dimensions by using tabletop coherent extreme ultraviolet (EUV) beams. Specifically, we characterize thermal transport and acoustic wave propagation in 3D periodic silicon inverse metalattices with <15nm characteristic dimensions. Measurements of the thermal transport demonstrate that metalattices may significantly impede heat flow, making them promising candidates for thermoelectric applications. Extraction of the acoustic wave dispersion down to ~100nm shows good agreement with finite element predictions, confirming that these semiconductor metalattices were fabricated with a very high-quality. These results demonstrate that EUV nanometrology is capable of extracting both dispersion relations, and thermal properties of 3D complex nano-systems, with applications including informed design and process control of nanoscale devices.

High-frequency surface acoustic wave propagation in nanostructures characterized by coherent extreme ultraviolet beams

2009 ◽  
Vol 94 (9) ◽  
pp. 093103 ◽  
Author(s):  
Mark E. Siemens ◽  
Qing Li ◽  
Margaret M. Murnane ◽  
Henry C. Kapteyn ◽  
Ronggui Yang ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
High Frequency ◽  
Extreme Ultraviolet ◽  
Acoustic Wave Propagation

scholarly journals Precise effective temperatures of solar analog stars

2011 ◽  
Vol 7 (S286) ◽  
pp. 328-331
Author(s):  
D. Cornejo-Espinoza ◽  
I. Ramírez ◽  
P. S. Barklem ◽  
W. Guevara-Day
Keyword(s):  
Spectroscopic Data ◽  
Spectral Lines ◽  
Atomic Data ◽  
Balmer Line ◽  
High Quality ◽  
Fine Grid ◽  
Fitting Procedure ◽  
Effective Temperatures ◽  
Very High ◽  
Good Agreement

AbstractWe perform a study of 62 solar analog stars to compute their effective temperatures (Teff) using the Balmer line wing fitting procedure and compare them with Teff values obtained using other commonly employed methods. We use observed Hα spectral lines and a fine grid of theoretical LTE model spectra calculated with the best available atomic data and most recent quantum theory. Our spectroscopic data are of very high quality and have been carefully normalized to recover the proper shape of the Hα line profile. We obtain Teff values with internal errors of about 25K. Comparison of our results with those from other methods shows reasonably good agreement. Then, combining Teff values obtained from four independent techniques, we are able to determine final Teff values with errors of about 10K.

Experimental and theoretical characterization of the surface acoustic wave propagation properties of GaN epitaxial layers on c-plane sapphire

2003 ◽  
Vol 18 (5) ◽  
pp. 1157-1161 ◽  
Author(s):  
Kook Hyun Choi ◽  
Hyeong Joon ◽  
Su Jin Chung ◽  
Jin Yong Kim ◽  
Tae Kun Lee ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Chemical Vapor ◽  
Epitaxial Layers ◽  
Experimental Characterization ◽  
Acoustic Wave Propagation ◽  
Matrix Methods ◽  
Propagation Properties ◽  
Good Agreement

Surface acoustic wave (SAW) propagation properties of gallium nitride (GaN) epitaxial layers on sapphire were theoretically and experimentally characterized. GaN thin films were grown on a c-plane sapphire substrate using a metalorganic chemical vapor deposition system. The experimental characterization of SAW propagation properties was performed with a linear array of interdigital transducer structures, while SAW velocities were calculated by matrix methods. Experimentally, we found pseudo-SAW and high-velocity pseudo-SAW modes in the GaN/sapphire structure, which had a good agreement with calculated velocities.

Thermal transport properties of carbon-carbon fibre composites III. Mathematical modelling

1990 ◽  
Vol 430 (1878) ◽  
pp. 199-211 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Transport ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Microstructural Characterization ◽  
Fibre Volume ◽  
Porosity Level ◽  
Using Data ◽  
Carbon Fibre Composites ◽  
Good Agreement

Measured thermal transport data are interpreted using data obtained by careful microstructural characterization concerning the porosity distribution and graphite grain sizes. The separate thermal conductivity components for one-dimensional composites are deduced using a simple series addition to determine ג f1 and ג m1 and using an adaptation of the Bruggeman analysis for calculating ג f┴ and ג m┴ . Parallel to the fibre axis the calculated thermal conductivities are shown to be in good agreement with existing theories of the thermal conductivity of graphite using experimentally determined values of grain size. The derived data are recombined in a simple series model to predict the thermal conductivity of two-dimensional composites containing a different fibre volume fraction and porosity level. Good agreement with measured data is obtained.

Study on the Influence of Roughness on the Detection for Mechanical Characteristics of the Machined Surface by Surface Acoustic Wave Dispersion Theory

2016 ◽  
Vol 693 ◽  
pp. 1447-1452
Author(s):  
Jing Lei Xu ◽  
Bin Lin ◽  
Ya Xu Wei
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Acoustic Waves ◽  
Mechanical Characteristics ◽  
Fractal Theory ◽  
Surface Acoustic Waves ◽  
Wave Dispersion ◽  
Acoustic Wave Propagation ◽  
Machined Surface

The surface acoustic wave (SAW) technique is a precise and nondestructive method to detect the mechanical characteristics of the precision-machined surface. The paper is concerned with the effect of the roughness of the machined surface on the dispersion of surface acoustic waves propagating in the precision-machined surface which indicates mechanical characteristics of the machined surface. The finite element method (FEM) is employed by establishing a series of models with different roughness Ra value to analyze influences from different roughness Ra value on surface acoustic wave dispersion. The models are established by applying a combined method based on fractal theory and wavelet analysis. The simulation results showed that the roughness of machined surface will cause the dispersion of surface acoustic wave propagation, the effect varies with the different roughness Ra values. A critical Ra value influencing on the surface acoustic wave propagation exists. Accordingly, that the factor of roughness should be considered in advance or not, the situation can be determined through studying and determining the critical roughness Ra value above mentioned. Consequently, the study has the important meaning regarding the detection for mechanical characteristics of the machined surface.

Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

1978 ◽  
Vol 36 (1) ◽  
pp. 594-595
Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd
Keyword(s):  
Flow Stress ◽  
Single Crystals ◽  
Room Temperature ◽  
Thin Foil ◽  
Age Hardening ◽  
Dispersion Strengthening ◽  
Accurate Picture ◽  
The Matrix ◽  
Very High ◽  
Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

Structural changes in silicon-on-insulator material during post-implantation annealing

1986 ◽  
Vol 44 ◽  
pp. 736-737
Author(s):  
C. O. Jung ◽  
S. J. Krause ◽  
S.R. Wilson
Keyword(s):  
Integrated Circuits ◽  
Oxide Layer ◽  
High Speed ◽  
Structural Changes ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
High Quality ◽  
Radiation Hardened ◽  
Post Implantation ◽  
Very High

Silicon-on-insulator (SOI) structures have excellent potential for future use in radiation hardened and high speed integrated circuits. For device fabrication in SOI material a high quality superficial Si layer above a buried oxide layer is required. Recently, Celler et al. reported that post-implantation annealing of oxygen implanted SOI at very high temperatures would eliminate virtually all defects and precipiates in the superficial Si layer. In this work we are reporting on the effect of three different post implantation annealing cycles on the structure of oxygen implanted SOI samples which were implanted under the same conditions.

Acoustic wave propagation in two dimensional sheared ducted flows

1997 ◽  
Author(s):  
E. Longatte ◽  
P. Lafon ◽  
S. Candel ◽  
E. Longatte ◽  
P. Lafon ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Two Dimensional ◽  
Acoustic Wave Propagation

WIELAND-K88

Alloy Digest ◽  
2005 ◽  
Vol 54 (12) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Stress Relaxation ◽  
Copper Alloy ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Relaxation Resistance ◽  
Temperature Performance ◽  
Very High

Abstract Wieland K-88 is a copper alloy with very high electrical and thermal conductivity, good strength, and excellent stress relaxation resistance at elevated temperatures. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CU-738. Producer or source: Wieland Metals Inc.

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