scholarly journals Stereo Measurement of Objects in Liquid and Estimation of Refractive Index of Liquid by Using Images of Water Surface

10.5772/12970 ◽  
2011 ◽  
Author(s):  
Atsushi Yamashita ◽  
Akira Fujii ◽  
Toru Kaneko
Keyword(s):  
Refractive Index ◽  
Water Surface

Over-water Refraction of 10-cm Electromagnetic Radiation

1947 ◽  
Vol 28 (1) ◽  
pp. 1-8 ◽  
Author(s):  
R. B. Montgomery
Keyword(s):  
Refractive Index ◽  
Water Surface ◽  
Dew Point ◽  
Radio Waves ◽  
Moist Air ◽  
Water Conditions ◽  
Spherical Earth ◽  
Vertical Distributions ◽  
Low Altitude

A simple presentation is made of the optics involved in the nearly horizontal propagation of short radio waves above the spherical earth. The refraction produced by various types of atmospheric layers is discussed, especially the refraction in atmospheric layers close to a water surface and the resulting wide variation in possible range of communication between low-altitude terminals. A formula showing how the refractive index of air at radio wave lengths depends on moist-air variables is reproduced. A graph for the determination of potential refractive index is presented. As examples of over-water conditions, the vertical distributions of temperature, dew point, and potential refractive index are shown for two psychrometric ascents by airplane to 1000 feet.

A small gear to enhance the observation of amber inclusions

2020 ◽  
Vol 3 (2) ◽  
pp. 156-157
Author(s):  
THOMAS SCHUBNEL ◽  
VALÉRIE NGÔ-MULLER ◽  
ANDRE NEL
Keyword(s):  
Refractive Index ◽  
Water Surface ◽  
Observation Angle ◽  
Objective Lens ◽  
Fossil Insects ◽  
Optical Medium

Paleoentomologists well know that the examination of fossil insects in amber is often complicated. Even if the amber is well-polished, the presence of small scratches at the surface and inner impurities generates reflections that limit observations. Prominent characters for taxonomy thus may not be visible even when preserved. Several solutions have been proposed to enhance the observation of fossil insects in amber. Most of them aim at limiting the number of optical medium interfaces, and thus reducing optical artefacts such as refraction and reflection. For example, amber may be embedded in Canada balsam or artificial resins (Azar & Nel, 1998; Green, 2001; Sidorchuk, 2013; Penney & Jepson, 2014; Sidorchuk & Vorontsov, 2018). However, these methods limit viewing angles and thus the observation of characters, are technically challenging and often irreversible. Another type of method is to immerse the piece of amber in a liquid with a refractive index as close as possible to the amber, such as sugared water, or oils (Sidorchuk, 2013). In this case, the interface between the objective lens and the amber is the coverslip that is placed on the surface of the liquid in order to avoid reflection on the water surface. Compounding the difficulty in observation is that an immersed piece of amber is observable only from one angle at a time, and the whole setting must be dismantled and reassembled to manually change the observation angle, which can result in a lengthy procedure.

Immunoferritin localization of intracellular antigens in positively stained frozen sections

1978 ◽  
Vol 36 (2) ◽  
pp. 168-169
Author(s):  
K. T. Tokuyasu
Keyword(s):  
Surface Tension ◽  
Water Surface ◽  
Thin Layers ◽  
The Other ◽  
Positive Staining ◽  
Frozen Sections ◽  
The Past ◽  
Ultrathin Frozen Sections ◽  
Definition Of

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).

TEM characterization of proton-exchanged LiNbO3 optical waveguides

1986 ◽  
Vol 44 ◽  
pp. 480-481
Author(s):  
W. E. Lee
Keyword(s):  
Refractive Index ◽  
Benzoic Acid ◽  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Lithium Ions ◽  
Wide Channel ◽  
Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

Light microscopy of ceramics

1993 ◽  
Vol 51 ◽  
pp. 908-909
Author(s):  
Walter C. McCrone
Keyword(s):  
Refractive Index ◽  
Light Microscopy ◽  
Light Microscope ◽  
Polarized Light ◽  
Refractive Indices ◽  
Complete Coverage ◽  
The Subject ◽  
Lower Refractive Index

An excellent chapter on this subject by V.D. Fréchette appeared in a book edited by L.L. Hench and R.W. Gould in 1971 (1). That chapter with the references cited there provides a very complete coverage of the subject. I will add a more complete coverage of an important polarized light microscope (PLM) technique developed more recently (2). Dispersion staining is based on refractive index and its variation with wavelength (dispersion of index). A particle of, say almandite, a garnet, has refractive indices of nF = 1.789 nm, nD = 1.780 nm and nC = 1.775 nm. A Cargille refractive index liquid having nD = 1.780 nm will have nF = 1.810 and nC = 1.768 nm. Almandite grains will disappear in that liquid when observed with a beam of 589 nm light (D-line), but it will have a lower refractive index than that liquid with 486 nm light (F-line), and a higher index than that liquid with 656 nm light (C-line).

A New Mounting Medium of High Refractive Index

1886 ◽  
Vol 21 (528supp) ◽  
pp. 8429-8430
Keyword(s):  
Refractive Index ◽  
High Refractive Index

On the refractive index of rutile

1992 ◽  
Vol 139 (2) ◽  
pp. 163 ◽  
Author(s):  
M.R. Shenoy ◽  
R.M. de la Rue
Keyword(s):  
Refractive Index
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