scholarly journals Measuring the spatial distribution of multiply scattered light using a de-scanned image sensor for examining retinal structure contrast

2021 ◽  
Vol 29 (2) ◽  
pp. 552
Author(s):  
Benjamin S. Sajdak ◽  
Jack T. Postlewaite ◽  
Kevin W. Eliceiri ◽  
Jeremy D. Rogers
Keyword(s):  
Spatial Distribution ◽  
Scattered Light ◽  
Image Sensor ◽  
Scanned Image ◽  
Retinal Structure

scholarly journals Local investigation of the optical properties of subwavelength rectangular holes with a focused beam of electrons

2011 ◽  
Vol 369 (1950) ◽  
pp. 3456-3471 ◽  
Author(s):  
J. C. Prangsma ◽  
D. van Oosten ◽  
L. Kuipers
Keyword(s):  
Optical Properties ◽  
Spatial Distribution ◽  
Gold Film ◽  
Scattered Light ◽  
Diffraction Limit ◽  
Optical Diffraction ◽  
Hole Shape ◽  
Small Clusters ◽  
Focused Beam ◽  
Shape And Size

The optical properties of rectangular subwavelength holes in a gold film are investigated using the light generated when a focused beam of electrons impinges on the sample close to the hole. Using this technique, multi-spectral maps of the holes are obtained with a resolution beyond the optical diffraction limit. The results show the influence of hole shape on the spectrum of locally scattered light. Rectangular holes of varying shape and size are investigated, and the spatial distribution of the polarization of the observed light is measured. The influence of neighbouring holes is investigated by measuring small clusters of holes.

A self-scanned image sensor employing MOS structure

1970 ◽  
Vol 58 (2) ◽  
pp. 247-248 ◽  
Author(s):  
T. Ando ◽  
Y. Ishihara ◽  
T. Akahoshi
Keyword(s):  
Image Sensor ◽  
Mos Structure ◽  
Scanned Image

Advanced mobile-DOAS techniuqes for locating and identifying urban area emission sources

2020 ◽  
Author(s):  
Zhaokun Hu ◽  
Ang Li ◽  
Pinhua Xie
Keyword(s):  
Spatial Distribution ◽  
Concentration Distribution ◽  
Column Density ◽  
High Spatial Resolution ◽  
Scattered Light ◽  
Pollutant Concentration ◽  
Emission Flux ◽  
Vertical Column ◽  
Vertical Column Density ◽  
Pollutant Concentration Distribution

<p>Pollutant concentration distribution and emission are important ways to understand regional pollution. To investigate the distribution characteristics and identify individual sources rapidly, a new mobile passive differential optical absorption spectroscopy (DOAS) instrument has been developed, which set two angle telescopes (90°,30°) to receive the scattered light respectively, and set two mechanical shutters to switch the optical path quickly in the mobile platform. The instrument collected the zenith scattered light in the UV or visible region and it was used to derive the vertical column density of trace gases above the measurement route. The slant column density in two different viewing directions were detected, and combined with the geometric approximation, the vertical column density of trace gas was obtained. After obtaining the column concentration distribution, the data were analyzed by semi variance analysis combined with geographical information. Monte Carlo simulation was used to reconstruct the high spatial resolution pollutant concentration distribution, combined the wind field data during the observation, the high spatial resolution emission flux in the area can be quickly obtained. A field experiment was performed in Beijing and some industrial area. The distribution information of vertical column density along the route in Beijing was derived, the concentration distribution of NO<sub>2</sub> at 200m *200m resolution and the 0.01° *0.01°resolution emission flux data are obtained further. The new mobile multi light DOAS instrument were operated on a car. The NO<sub>2</sub> column density spatial distribution and the emission flux spatial distribution are obtained with the maximum value of 8.57×1016 molec./cm<sup>2</sup> and 34.8 ug/m<sup>2</sup>/s over the Beijing fifth ring road area. The scheme can provide a new method to verify pollutant concentration distribution and emission inventory.</p>

Lithography below 100 nm

1983 ◽  
Vol 41 ◽  
pp. 96-99
Author(s):  
L. D. Jackel
Keyword(s):  
Spatial Distribution ◽  
Electron Beam ◽  
Electron Scattering ◽  
Electron Beam Lithography ◽  
Substrate Material ◽  
Local Electron ◽  
Electron Dose ◽  
Positive Resist ◽  
Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

SEM evaluation of the TEM cold-stage double-film specimen

1984 ◽  
Vol 42 ◽  
pp. 272-273
Author(s):  
Jayesh Bellare
Keyword(s):  
Spatial Distribution ◽  
Sample Preparation ◽  
Sample Thickness ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Liquid Sample ◽  
Thin Specimen ◽  
Sample Preparation Technique ◽  
Cold Stage ◽  
Film Specimen

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.

Macroprobe Mode for the Study of Segregation in Steels

1990 ◽  
Vol 48 (2) ◽  
pp. 260-261
Author(s):  
Auclair Gilles ◽  
Benoit Danièle
Keyword(s):  
Mechanical Properties ◽  
Spatial Distribution ◽  
High Performance ◽  
Volume Fraction ◽  
Sheet Steel ◽  
Acquisition Time ◽  
Chemical Information ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Optical Micrographs

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.

Ultrastructural analysis of the spatial distribution of MRNA

1992 ◽  
Vol 50 (1) ◽  
pp. 552-553
Author(s):  
Gary Bassell ◽  
Robert H. Singer
Keyword(s):  
Electron Microscopy ◽  
Spatial Distribution ◽  
In Situ Hybridization ◽  
High Resolution ◽  
Nucleic Acids ◽  
Colloidal Gold ◽  
Dna Probe ◽  
Nucleotide Analogs ◽  
Gold Particles

We have been investigating the spatial distribution of nucleic acids intracellularly using in situ hybridization. The use of non-isotopic nucleotide analogs incorporated into the DNA probe allows the detection of the probe at its site of hybridization within the cell. This approach therefore is compatible with the high resolution available by electron microscopy. Biotinated or digoxigenated probe can be detected by antibodies conjugated to colloidal gold. Because mRNA serves as a template for the probe fragments, the colloidal gold particles are detected as arrays which allow it to be unequivocally distinguished from background.

Membrane microdomains: lessons from microscopy

1995 ◽  
Vol 53 ◽  
pp. 776-777
Author(s):  
J.M. Robinson ◽  
J.M Oliver
Keyword(s):  
Spatial Distribution ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Plasma Membranes ◽  
Cell Types ◽  
Imaging Modalities ◽  
Membrane Microdomains ◽  
Membrane Domains ◽  
Lateral Heterogeneity ◽  
Functional Importance

Specialized regions of plasma membranes displaying lateral heterogeneity are the focus of this Symposium. Specialized membrane domains are known for certain cell types such as differentiated epithelial cells where lateral heterogeneity in lipids and proteins exists between the apical and basolateral portions of the plasma membrane. Lateral heterogeneity and the presence of microdomains in membranes that are uniform in appearance have been more difficult to establish. Nonetheless a number of studies have provided evidence for membrane microdomains and indicated a functional importance for these structures.This symposium will focus on the use of various imaging modalities and related approaches to define membrane microdomains in a number of cell types. The importance of existing as well as emerging imaging technologies for use in the elucidation of membrane microdomains will be highlighted. The organization of membrane microdomains in terms of dimensions and spatial distribution is of considerable interest and will be addressed in this Symposium.

An analytical microscopic study of metals in fluidized catalytic cracking catalyst

1986 ◽  
Vol 44 ◽  
pp. 854-855
Author(s):  
Clifford S. Rainey
Keyword(s):  
Electron Microscopy ◽  
Spatial Distribution ◽  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Coke Formation ◽  
Acid Sites ◽  
Y Zeolite ◽  
Fcc Catalyst ◽  
Fluidized Catalytic Cracking ◽  
High Regeneration

The spatial distribution of V and Ni deposited within fluidized catalytic cracking (FCC) catalyst is studied because these metals contribute to catalyst deactivation. Y zeolite in FCC microspheres are high SiO2 aluminosilicates with molecular-sized channels that contain a mixture of lanthanoids. They must withstand high regeneration temperatures and retain acid sites needed for cracking of hydrocarbons, a process essential for efficient gasoline production. Zeolite in combination with V to form vanadates, or less diffusion in the channels due to coke formation, may deactivate catalyst. Other factors such as metal "skins", microsphere sintering, and attrition may also be involved. SEM of FCC fracture surfaces, AEM of Y zeolite, and electron microscopy of this work are developed to better understand and minimize catalyst deactivation.

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