Single-layer TiO_2 and multilayer TiO_2–SiO_2 optical coatings prepared from colloidal suspensions

1987 ◽  
Vol 26 (21) ◽  
pp. 4688 ◽  
Author(s):  
Ian M. Thomas
Keyword(s):  
Single Layer ◽  
Colloidal Suspensions ◽  
Optical Coatings

Buckling of a Confined Colloidal Crystal

1992 ◽  
Vol 290 ◽  
Author(s):  
T. Chou ◽  
D. R. Nelson
Keyword(s):  
Colloidal Crystal ◽  
Single Layer ◽  
Colloidal Suspensions ◽  
Plate Separation

AbstractThe behavior of colloidal suspensions confined between two plates narrowly spaced is examined. When plate separations are small, only one layer of particles can be confined; however, as plate separation is increased, multiple layers will eventually form. These layers can exist in a variety of structures depending on the energetics of packing. We examine the unstable modes which form as a single layer buckles on its way to forming two layers. Three ordered states are found; which one is selected depends on the form of the interparticle and wall potentials.

High-Performance, Single-Layer Antireflective Optical Coatings Comprising Mesoporous Silica Nanoparticles

2012 ◽  
Vol 4 (2) ◽  
pp. 854-859 ◽  
Author(s):  
Jonathan Moghal ◽  
Johannes Kobler ◽  
Jürgen Sauer ◽  
James Best ◽  
Martin Gardener ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
High Performance ◽  
Mesoporous Silica Nanoparticles ◽  
Single Layer ◽  
Optical Coatings

Stabilization, Characterization and Optical Applications of Niobium and Tantalum Oxide Sols Prepared Via Alkoxide Routes

1990 ◽  
Vol 180 ◽  
Author(s):  
Stephen Parraud ◽  
Liliane G. Hubert-Pfalzgraf ◽  
Herve Floch
Keyword(s):  
Spin Coating ◽  
Tantalum Oxide ◽  
Pulse Length ◽  
Single Layer ◽  
Colloidal Suspensions ◽  
Laser Damage ◽  
Threshold Values ◽  
Small Particles ◽  
Optical Applications ◽  
Hydrolysis Of

ABSTRACTHydrolysis of niobium and tantalum pentaethoxides in ethanol and in the presence of basic (ammonia, tetramethylammonium hydroxide, di and triethylamine) or acidic (nitric or hydrochloric acids) additives was investigated. Triethylamine gives monodispersed, small particles of amorphous M2O5,nH2O (M = Nb, Ta). These colloidal suspensions were used to obtain thin films by spin-coating techniques. The coatings display a thickness of 100–300 nm and a refractive index around 1.7. Laser damage tests at 1064 nm wavelength with a pulse length of 3 ns were carried out on the single layer systems. The threshold values (one-onone) are in favor of the Ta2O5 coatings with an average of 14.5 ± 2.1 J/cm2 , by comparison with 8.3 ± 1.6 J/cm2 for the Nb2O5 films.

Crystalline order to a resolution of 4.7 A in the sheath of Methanospirilium hungatii: A cross-beta structure

1984 ◽  
Vol 42 ◽  
pp. 214-215
Author(s):  
Murray Stewart ◽  
T.J. Beveridge ◽  
D. Sprott
Keyword(s):  
Cell Wall ◽  
Single Layer ◽  
Uranyl Acetate ◽  
Optical Diffraction ◽  
Tube Axis ◽  
Basic Subunit ◽  
Beta Structure ◽  
Diffraction Patterns ◽  
Protein Treatment ◽  
General Appearance

The archaebacterium Methanospirillum hungatii has a sheath as part of its cell wall which is composed mainly of protein. Treatment with dithiothreitol or NaOH released the intact sheaths and electron micrographs of this material negatively stained with uranyl acetate showed flattened hollow tubes, about 0.5 μm diameter and several microns long, in which the patterns from the top and bottom were superimposed. Single layers, derived from broken tubes, were also seen and were more simply analysed. Figure 1 shows the general appearance of a single layer. There was a faint axial periodicity at 28.5 A, which was stronger at irregular multiples of 28.5 A (3 and 4 times were most common), and fine striations were also seen at about 3° to the tube axis. Low angle electron diffraction patterns (not shown) and optical diffraction patterns (Fig. 2) from these layers showed a complex meridian (as a result of the irregular nature of the repeat along the tube axis) which showed a clear maximum at 28.5 A, consistent with the basic subunit spacing.

Differentiation Processes of the Ocellar Retina of the Honeybee (Apis Mellifera L.)

1990 ◽  
Vol 48 (3) ◽  
pp. 430-431
Author(s):  
Maria Anna Pabst
Keyword(s):  
Apis Mellifera ◽  
Distal Part ◽  
Cell Layer ◽  
Single Layer ◽  
Photoreceptor Cells ◽  
Distal Segment ◽  
Compound Eyes ◽  
Thin Sections ◽  
Ultrastructural Studies ◽  
Adult Worker

In addition to the compound eyes, honeybees have three dorsal ocelli on the vertex of the head. Each ocellus has about 800 elongated photoreceptor cells. They are paired and the distal segment of each pair bears densely packed microvilli forming together a platelike fused rhabdom. Beneath a common cuticular lens a single layer of corneagenous cells is present.Ultrastructural studies were made of the retina of praepupae, different pupal stages and adult worker bees by thin sections and freeze-etch preparations. In praepupae the ocellar anlage consists of a conical group of epidermal cells that differentiate to photoreceptor cells, glial cells and corneagenous cells. Some photoreceptor cells are already paired and show disarrayed microvilli with circularly ordered filaments inside. In ocelli of 2-day-old pupae, when a retinogenous and a lentinogenous cell layer can be clearly distinguished, cell membranes of the distal part of two photoreceptor cells begin to interdigitate with each other and so start to form the definitive microvilli. At the beginning the microvilli often occupy the whole width of the developing rhabdom (Fig. 1).

Characterization of a monolayer graphitic structure

1994 ◽  
Vol 52 ◽  
pp. 760-761
Author(s):  
X. Lin ◽  
X. K. Wang ◽  
V. P. Dravid ◽  
J. B. Ketterson ◽  
R. P. H. Chang
Keyword(s):  
Three Dimensional ◽  
Single Layer ◽  
Synthesis Process ◽  
Graphitic Structure ◽  
Positive Gaussian Curvature ◽  
Graphitic Sheet ◽  
Structural And Electronic Properties ◽  
New Material ◽  
Hexagonal Network

For small curvatures of a graphitic sheet, carbon atoms can maintain their preferred sp2 bonding while allowing the sheet to have various three-dimensional geometries, which may have exotic structural and electronic properties. In addition the fivefold rings will lead to a positive Gaussian curvature in the hexagonal network, and the sevenfold rings cause a negative one. By combining these sevenfold and fivefold rings with sixfold rings, it is possible to construct complicated carbon sp2 networks. Because it is much easier to introduce pentagons and heptagons into the single-layer hexagonal network than into the multilayer network, the complicated morphologies would be more common in the single-layer graphite structures. In this contribution, we report the observation and characterization of a new material of monolayer graphitic structure by electron diffraction, HREM, EELS.The synthesis process used in this study is reported early. We utilized a composite anode of graphite and copper for arc evaporation in helium.

A metal- coating Chamber for High-Resolution Cryo-SEM

1990 ◽  
Vol 48 (1) ◽  
pp. 418-419
Author(s):  
John G. Sheehan
Keyword(s):  
High Resolution ◽  
Colloidal Suspensions ◽  
Metal Coating ◽  
Colloidal Interactions ◽  
Amorphous Ice ◽  
High Vapor ◽  
Particulate Coatings ◽  
20 Nm ◽  
Film Nucleation ◽  
Coating Chamber

Improvements in particulate coatings for printable paper require understanding mechanisms of colloidal interactions in paper coating suspensions. One way to deduce colloidal interactions is to mage particle spacings and orientations at high resolution with cryo-SEM. Recent improvements in cryo-SEM technique have increased resolution enough to image particles in coating paints,vhich are sometimes smaller than 100 nm. In this report, a metal-coating chamber is described for preparation of colloidal suspensions for cryo-SEM at resolution down to 20 nm. It was found that etching is not necessary to achieve this resolution.A 120 K cryo-SEM sample will remain in an SEM for hours without noticeable condensation of imorphous ice. This is due to the high vapor pressure of vapor-condensed amorphous ice, measured by Kouchi. However, clean vacuum is required to coat samples with the thinnest possible continuous metal films which are required for high magnification SEM. Vapor contaminants, especially hrydrocarbons, are known to interfere with thin-film nucleation and growth so that more metal is needed to form continuous films, and resolution is decreased. That is why the metal-coating chamber in fig. 1 is designed for the cleanest possible vacuum. Feedthroughs for the manipulator md the shutter, which are operated during metal coating, are sealed with leak-proof stainless-steel Dellows. The transfer rod slides through a baseplate feedthrough that is double o-ring sealed.

The Continuous Single-Layer Anastomosis in the Gastrointestinal Tract

Swiss Surgery ◽  
2003 ◽  
Vol 9 (3) ◽  
pp. 114-120 ◽  
Author(s):  
Steinke ◽  
Leippold ◽  
Schweizer
Keyword(s):  
Gastrointestinal Tract ◽  
Single Layer

Über die Frage der besten oder "richtigen" Technik bei gastrointestinalen Anastomosen wird seit je diskutiert. Die Ansprüche an eine gute Anastomosentechnik sind: Gute Durchblutung, Wasserdichtigkeit, Spannungsfreiheit, Sicherheit, leichte Durchführbarkeit, wenig Unruhe und Verschmutzung im Operationsgebiet und geringe Kosten. Die Operationstechnik der extramukösen, fortlaufenden Anastomosentechnik im Gastrointestinaltrakt wird in Wort und Bild erläutert. Anhand einer Pilotstudie, einer randomisierten Vergleichsstudie, einer Schweizer Multizenterstudie und schliesslich einer 5-jährigen Qualitätskontrollstudie wird gezeigt, dass diese "Schweizer"-Technik allen Anforderungen zur Durchführung einer "idealen" Anastomose gerecht wird und an fast allen intestinalen Lokalisationen verwendet werden kann.

Sign in / Sign up

Export Citation Format

Share Document