Photoelectrical characterization of photorefractive organic systems

1999 ◽  
Author(s):  
Stephan J. Zilker ◽  
M. Grasruck ◽  
Andre Leopold ◽  
Uwe Hofmann ◽  
M. A. Kol'chenko ◽  
...  
Keyword(s):  
Organic Systems

Characterization of clays and clay–organic systems. Cation diffusion and dehydroxylation

1986 ◽  
Vol 82 (2) ◽  
pp. 545 ◽  
Author(s):  
D. Tilak B. Tennakoon ◽  
John M. Thomas ◽  
William Jones ◽  
T. Adrian Carpenter ◽  
Subramaniam Ramdas
Keyword(s):  
Cation Diffusion ◽  
Organic Systems

The characterization of clay-organic systems

Clay Minerals ◽  
1982 ◽  
Vol 18 (4) ◽  
pp. 357-371 ◽  
Author(s):  
D. T. B. Tennakoon ◽  
R. Schlögl ◽  
T. Rayment ◽  
J. Klinowski ◽  
W. Jones ◽  
...  
Keyword(s):  
High Pressure ◽  
Nmr Spectroscopy ◽  
Catalytic Properties ◽  
Clear Distinction ◽  
Organic Systems ◽  
Catalytically Active ◽  
Natural Clays ◽  
Temperature Controlled ◽  
C Nmr

AbstractThe importance of a number of techniques (including1H and13C NMR, XRD and IR) in exploring the important catalytic properties of synthetic and natural clays is described. A clear distinction is observed between proven catalytically-active clays (e.g. Al-exchanged) and those which are generally less effective (e.g. Na-exchanged).13C NMR spectroscopy is used to identify directly products formed within the interlayer regions, and temperature-controlled powder XRD serves as a useful tool for identifying whether or not intercalation occurs under variously defined conditions. High-pressure XRD is used to verify the formation of different products during reaction.

scholarly journals Characterization of Binary Organogels Based on Some Azobenzene Compounds and Alkyloxybenzoic Acids with Different Chain Lengths

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Yongmei Hu ◽  
Qingshan Li ◽  
Wei Hong ◽  
Tifeng Jiao ◽  
Guangzhong Xing ◽  
...  
Keyword(s):  
Organic Solvents ◽  
Alkyl Substituent ◽  
Morphological Characterization ◽  
Hydrophobic Force ◽  
Multilayer Nanostructures ◽  
Textile Materials ◽  
Alkyl Chains ◽  
Organic Systems ◽  
Chain Lengths

In this work the gelation behaviors of binary organogels composed of azobenzene amino derivatives and alkyloxybenzoic acids with different lengths of alkyl chains in various organic solvents were investigated and characterized. The corresponding gelation behaviors in 20 solvents were characterized and shown as new binary organic systems. It showed that the lengths of substituent alkyl chains in compounds have played an important role in the gelation formation of gelator mixtures in present tested organic solvents. Longer methylene chains in molecular skeletons in these gelators seem more suitable for the gelation of present solvents. Morphological characterization showed that these gelator molecules have the tendency to self-assemble into various aggregates from lamella, wrinkle, and belt to dot with change of solvents and gelator mixtures. Spectral characterization demonstrated different H-bond formation and hydrophobic force existing in gels, depending on different substituent chains in molecular skeletons. Meanwhile, these organogels can self-assemble to form monomolecular or multilayer nanostructures owing to the different lengths of due to alkyl substituent chains. Possible assembly modes for present xerogels were proposed. The present investigation is perspective to provide new clues for the design of new nanomaterials and functional textile materials with special microstructures.

Synthesis & Characterization of Optically-Active Lanthanide-Doped Hybrid Inorganic-Organic Systems

1999 ◽  
Vol 576 ◽  
Author(s):  
R.E. Taylor-Smith ◽  
K. M. Choi
Keyword(s):  
Sol Gel ◽  
Systems Design ◽  
Optically Active ◽  
Materials Chemistry ◽  
Active Systems ◽  
Organic Systems ◽  
Bridged Silsesquioxane ◽  
Molecular Composites ◽  
Rare Earth Doped

ABSTRACTThe materials chemistry of sol-gel-derived inorganic-organic molecular composites offers significant potential for molecular-level systems design. One focus in this arena is the chemical design and microstructural engineering of optically-active systems. We report the generation of rare-earth-doped inorganic-organic hybrids, based on a bridged polysilsesquioxane architecture. Derived from lanthanide precursors such as Erbium isopropoxide, which we co-condense with the requisite silsesquioxane monomer, these systems exhibit significant optical activity. In experiments on hybrids doped with Erbium, we conclusively demonstrate strong fluorescence at wavelengths in the vicinity of 1540 nm, from stimulation with 488 nm radiation. We discuss materials-driven impacts of the bridged-silsesquioxane architecture on system complexities arising from the solution sol-gel route which would affect fluorescence efficiencies and luminescence levels, such as hydroxyl impurities and clustering-effects.

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

Characterization of Coherent, Ordered Precipitates in Nickel-Base Alloys

1973 ◽  
Vol 31 ◽  
pp. 144-145
Author(s):  
B. H. Kear ◽  
J. M. Oblak
Keyword(s):  
Stable Phase ◽  
Nickel Base Superalloy ◽  
Alloy 718 ◽  
Commercial Alloy ◽  
Precipitate Morphology ◽  
Continuous Precipitation ◽  
Nickel Base ◽  
Base Superalloy ◽  
Strengthening Precipitate

A nickel-base superalloy is essentially a Ni/Cr solid solution hardened by additions of Al (Ti, Nb, etc.) to precipitate a coherent, ordered phase. In most commercial alloy systems, e.g. B-1900, IN-100 and Mar-M200, the stable precipitate is Ni3 (Al,Ti) γ′, with an LI2structure. In A lloy 901 the normal precipitate is metastable Nis Ti3 γ′ ; the stable phase is a hexagonal Do2 4 structure. In Alloy 718 the strengthening precipitate is metastable γ″, which has a body-centered tetragonal D022 structure.Precipitate MorphologyIn most systems the ordered γ′ phase forms by a continuous precipitation re-action, which gives rise to a uniform intragranular dispersion of precipitate particles. For zero γ/γ′ misfit, the γ′ precipitates assume a spheroidal.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

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