Reflectance from solids and solid particles: the need for the optical constants n and k and far-IR measurement challenges

2018 ◽  
Author(s):  
Timothy J. Johnson ◽  
Brent M. De Vetter ◽  
Bret D. Cannon ◽  
Tanya L. Myers ◽  
Nicole K. Scharko ◽  
...  
Keyword(s):  
Optical Constants ◽  
Solid Particles

On the Importance of Producing and Characterizing Laboratory Analogs of Planetary Atmospheric Aerosols and Clouds and Their Use to Interpret Observations

2021 ◽  
Author(s):  
Ella Sciamma-O'Brien ◽  
Erika Barth ◽  
Tanguy Bertrand ◽  
Jason Cook ◽  
Dale Cruikshank ◽  
...  
Keyword(s):  
Observational Data ◽  
Atmospheric Aerosols ◽  
Optical Constants ◽  
Experimental Studies ◽  
Planetary Atmospheres ◽  
Solid Particles ◽  
Vapor Pressures ◽  
Cloud Particle ◽  
Molecular Precursors ◽  
Cloud Particles

<p>Clouds and hazes play a major role in (exo)planetary atmospheres. They can absorb and reflect light from UV to thermal infrared wavelengths, changing the atmospheric emission, reflection, and transmission spectra dramatically. The organic aerosols forming the haze can act as cloud condensation nuclei. Then can also settle down onto the surface, hence participating in its composition. Dedicated laboratory experiments have been developed to produce solid materials that are analogs of haze and cloud particles, under different experimental conditions (molecular precursors, temperature, pressure, energy source…). These experimental studies are key to investigating the physical and chemical processes that drive the formation of solid particles from gas and solid phase molecular precursors in planetary environments. These experiments also allow the characterization of the physical, optical and chemical properties of the laboratory-generated haze and cloud particle analogs, hence providing critical information that can be used as input parameters in models for the analysis and interpretation of observational data (e.g. optical constants, vapor pressures, spectral features, grain morphology, etc).</p><p>Here, as examples of these laboratory efforts, we will present various studies that combine (1) experiments performed to produce analogs of Titan and Pluto atmospheric aerosols from gas phase molecular precursors, (2) experiments conducted to simulate the formation of benzene ice cloud particles in Titan’s stratosphere, and (3) experiments carried out to characterize the haze and cloud particle analogs to provide, in particular, optical constants and vapor pressures. We will show how important these studies are for the interpretation of observational data from past, current and future (exo)planetary missions. We will also introduce the newly funded NASA Center for Optical Constants whose overarching goal is to support a stable, long-term, synergistic laboratory effort to address a critical need throughout the broader planetary science community for the development of a comprehensive database containing complex refractive indices (optical constants) of laboratory-generated analogs of organic refractory materials, and ices present in planetary atmospheres and surfaces.</p>

Development of 200kV ultrahigh-resolution analytical electron microscope

1989 ◽  
Vol 47 ◽  
pp. 108-109
Author(s):  
T. Kaneyama ◽  
M. Naruse ◽  
Y. Ishida ◽  
M. Kersker
Keyword(s):  
Electron Microscope ◽  
Optical Constants ◽  
Materials Science ◽  
Objective Lens ◽  
The Finite Element Method ◽  
Ultrahigh Resolution ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Characteristic Features ◽  
Better Than

In the field of materials science, the importance of the ultrahigh resolution analytical electron microscope (UHRAEM) is increasing. A new UHRAEM which provides a resolution of better than 0.2 nm and allows analysis of a few nm areas has been developed. [Fig. 1 shows the external view] The followings are some characteristic features of the UHRAEM.Objective lens (OL)Two types of OL polepieces (URP for ±10' specimen tilt and ARP for ±30' tilt) have been developed. The optical constants shown in the table on the next page are figures calculated by the finite element method. However, Cs was experimentally confirmed by two methods (namely, Beam Tilt method and Krivanek method) as 0.45 ∼ 0.50 mm for URP and as 0.9 ∼ 1.0 mm for ARP, respectively. Fig. 2 shows an optical diffractogram obtained from a micrograph of amorphous carbon with URP under the Scherzer defocus condition. It demonstrates a resolution of 0.19 nm and a Cs smaller than 0.5 mm.

OPTICAL CONSTANTS OF LAYER STRUCTURES FROM ELLIPSOMETRIC DATA

1983 ◽  
Vol 44 (C10) ◽  
pp. C10-31-C10-34
Author(s):  
S. Logothetidis ◽  
J. Spyridelis
Keyword(s):  
Optical Constants ◽  
Layer Structures

Abrasive wear of polymer/steel gear drives

2008 ◽  
Vol 4 (1) ◽  
pp. 1-26
Author(s):  
Gábor Kalácska
Keyword(s):  
Wear Resistance ◽  
Abrasive Wear ◽  
Material Selection ◽  
Solid Particles ◽  
Soil Types ◽  
General View ◽  
Modern Engineering ◽  
Clean Environment ◽  
Engineering Polymers ◽  
Plastic Gears

Research was performed on the friction, wear and efficiency of plastic gears made of modern engineering polymers and their composites both in a clean environment (adhesive sliding surfaces) and in an environment contaminated with solid particles and dust (abrasive), with no lubrication at all. The purpose is to give a general view about the results of abrasive wear tests including seven soil types as abrasive media. At the first stage of the research silicious sand was applied between the meshing gears and the wear of plastic and steel gears was evaluated and analyzed from the point of different material properties (elongation at break, hardness, yield stress, modulus of elasticity) and its combinations. The different correlations between the experienced wear and material features are also introduced. At the second stage of the project the abrasive sand was replaced with different physical soil types. The abrasive wear of gears is plotted in the function of soil types. The results highlight on the considerable role of physical soil types on abrasive wear resistance and the conclusions contain the detailed wear resistance. The results offer a new tribology database for the operation and maintenance of agricultural machines with the opportunity of a better material selection according to the dominant soil type. This can finally result longer lifetime and higher reliability of wearing plastic/steel parts.

INVERSE PROBLEMS METHOD FOR STUDY OF HEAT TRANSFER IN SOLIDS INTERACTED WITH GAS FLOWS LOADED BY SOLID PARTICLES

Equipment ◽  
2006 ◽  
Author(s):  
Aleksey V. Nenarokomov ◽  
O. M. Alifanov ◽  
E. A. Artioukhine ◽  
I. V. Repin
Keyword(s):  
Heat Transfer ◽  
Inverse Problems ◽  
Solid Particles ◽  
Gas Flows

Flow and Heat Transfer Within Segregated Beds of Solid Particles

2001 ◽  
Vol 4 (3) ◽  
pp. 10 ◽  
Author(s):  
Abdulmajeed A. Mohamad ◽  
G. A. Karim
Keyword(s):  
Heat Transfer ◽  
Solid Particles ◽  
Flow And Heat Transfer
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