Multilayer Materials

MRS Bulletin ◽  
1990 ◽  
Vol 15 (2) ◽  
pp. 17-18 ◽  
Author(s):  
Troy W. Barbee
Keyword(s):  
Atomic Layer ◽  
Image Transmission ◽  
General Concept ◽  
Transmission Electron Micrograph ◽  
Electron Micrograph ◽  
Lattice Image ◽  
Structure Variation ◽  
Composition And Structure ◽  
Titanium Nickel ◽  
Composition Structure

Multilayers, as considered in the following articles, are manmade thin-film materials periodic in one dimension in composition or in composition and structure. This composition/structure variation is generated during synthesis, which is typically accomplished using atom-by-atom technologies. Individual component layers in a multilayer may vary in thickness from one atomic layer (~2 Å) to hundreds of atomic layers (~1,000 Å) of a given material.An example of these synthetic micro-structures, a lattice image transmission electron micrograph of a cross section of a hundred period titanium (63 Å)/titanium-nickel (40 Å) multilayer microstructure fabricated using magnetron sputtering, is shown on the cover of this issue of the MRS BULLETIN. The titanium-nickel layers are amorphous as a result of the low substrate temperature (<75°C) and the very large atomic quench rates characteristic of vapor deposition (>1012 K/s). The elemental titanium layers are fiber textured with the basal plane of this hexagonal close-pack structure element in the plane of the layers. These (00.1) planes are the ones lattice imaged in this electron micrograph.The general concept of a multilayer structure, as illustrated above, is now well accepted because the ability to synthesize such materials for scientific study and technological application has been demonstrated at many nationally and internationally based laboratories.

Undecagold labeling of tRNA

1991 ◽  
Vol 49 ◽  
pp. 44-45
Author(s):  
James F. Hainfeld ◽  
Kyra M. Alford ◽  
Mathias Sprinzl ◽  
Valsan Mandiyan ◽  
Santa J. Tumminia ◽  
...  
Keyword(s):  
High Resolution ◽  
Transmission Electron Micrograph ◽  
Anticodon Loop ◽  
Electron Micrograph ◽  
Reaction Conditions ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

The undecagold (Au11) cluster was used to covalently label tRNA molecules at two specific ribonucleotides, one at position 75, and one at position 32 near the anticodon loop. Two different Au11 derivatives were used, one with a monomaleimide and one with a monoiodacetamide to effect efficient reactions.The first tRNA labeled was yeast tRNAphe which had a 2-thiocytidine (s2C) enzymatically introduced at position 75. This was found to react with the iodoacetamide-Aun derivative (Fig. 1) but not the maleimide-Aun (Fig. 2). Reaction conditions were 37° for 16 hours. Addition of dimethylformamide (DMF) up to 70% made no improvement in the labeling yield. A high resolution scanning transmission electron micrograph (STEM) taken using the darkfield elastically scattered electrons is shown in Fig. 3.

Ge-Related Interfacial Defects in Sige Alloy Structures

1995 ◽  
Vol 405 ◽  
Author(s):  
Patricia J. Macfarlane ◽  
M. E. Zvanut ◽  
W. E. Carlos ◽  
M. E. Twigg ◽  
P. E. Thompson
Keyword(s):  
Depth Profile ◽  
Epr Spectra ◽  
Transmission Electron Micrograph ◽  
Dangling Bond ◽  
Electron Micrograph ◽  
Cross Sectional ◽  
Paramagnetic Resonance ◽  
Transmission Electron ◽  
Interfacial Defects ◽  
Electron Paramagnetic

AbstractThis paper reports etching results supporting the identification of the SG1 center as a germanium dangling bond defect at the interface between an oxide and crystalline SiGe. The presence of this defect is significant because, like an analogous center in Si-based systems, it may alter the operation of any microelectronic or micro-optical device which incorporates an interface between SiGe and an overlying oxide. The samples examined are oxygen implanted SiGe layers in which the SG1 center is believed to occur at the interface between oxide precipitates and SiGe. Because of the center's apparent relation to the oxide precipitates distributed through layers of the sample, a depth profile assists in confirming the interfacial nature of the defect. We obtain a depth profile by comparing electron paramagnetic resonance (EPR) spectra of samples etched to decreasing thickness. EPR spectra indicate that the SG1 center decreases with depth in a manner that when correlated to a cross sectional transmission electron micrograph confirms the association with SiO2 and supports its location at the SiGe/SiO2 precipitate interface.

Composition and structure variation for magnetron sputtered tantalum oxynitride thin films, as function of deposition parameters

2015 ◽  
Vol 358 ◽  
pp. 508-517 ◽  
Author(s):  
D. Cristea ◽  
M. Pătru ◽  
A. Crisan ◽  
D. Munteanu ◽  
D. Crăciun ◽  
...  
Keyword(s):  
Thin Films ◽  
Structure Variation ◽  
Deposition Parameters ◽  
Composition And Structure

NANOSEEDING EFFECT IN ZSM-5 CRYSTALLIZATION PROCESS

NANO ◽  
2013 ◽  
Vol 08 (03) ◽  
pp. 1350027
Author(s):  
YI LU ◽  
NAI-QIAN ZHANG ◽  
QIN TONG ◽  
JIN-KU LIU ◽  
DAN-JING HONG
Keyword(s):  
Crystallization Process ◽  
Nitrogen Adsorption ◽  
Particle Size Effect ◽  
Isomerization Reaction ◽  
Transmission Electron Micrograph ◽  
Electron Micrograph ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Induction System ◽  
Temperature Programmed

ZSM-5 zeolites were hydrothermally synthesized in three different seeding pathways under the direction of tetrapropylammonium bromide (TPABr) template. In order to investigate the seeding effect in ZSM-5 crystallization process, ZSM-5 crystals and pre-fabricated MFI-type nanoseeds were added into the original self-induction system, respectively. The final ZSM-5 zeolites were systematically investigated based on XRD (X-ray diffraction), SEM (scanning electron micrograph), TEM (transmission electron micrograph), nitrogen adsorption characterizations and NH3 -TPD (ammonia-temperature programmed desorption). The self-induction system produced ca. 20 μm ZSM-5 zeolite displaying hexagonally uniform prisms. After the addition of ZSM-5 crystal seeds, the crystal sizes were decreased greatly to ca. 5 μm. When MFI-type nanoseeds were adopted, irregular aggregate particles consisting of 20–50 nm primary particles were rapidly synthesized. The varied hydrothermal crystallization kinetics of the three synthesis system was also explored. Adjusting the seed agents alone, ZSM-5 crystals with diverse structural, morphological, textural and hydrothermal behaviors could be fabricated conveniently. The three ZSM-5 zeolites loaded by 0.05 wt.% Pt were assessed for the xylene isomerization reaction to investigate the particle size effect on the catalytic properties.

LOW ENERGY ION SCATTERING

2007 ◽  
Vol 14 (01) ◽  
pp. 31-41 ◽  
Author(s):  
FERIDOUN SAMAVAT ◽  
BRUCE V. KING ◽  
D. JOHN O'CONNOR
Keyword(s):  
Surface Analysis ◽  
Atomic Layer ◽  
Low Energy ◽  
Surface Atom ◽  
Ion Scattering ◽  
Low Energy Ion Scattering ◽  
Composition And Structure ◽  
Extreme Sensitivity ◽  
Low Energy Ions

Low energy ion scattering (LEIS) is the study of the composition and structure of a surface by the detection of low energy ions with energies ranging from 100 eV to 10 keV elastically scattered off the surface. The extreme sensitivity to the outermost atomic layer makes it as a unique tool for surface analysis. In this paper, concepts of shadowing, blocking, and also polar and azimuthal scans have been described. Surface order and surface atom spacings are revealed by using these concepts and measuring the intensity of backscattered projectiles as a function of the incident and azimuthal angles.

Ge-Related Interfacial Defects In SiGe Alloy Structures

1995 ◽  
Vol 406 ◽  
Author(s):  
Patricia J. Macfarlane ◽  
M. E. Zvanut ◽  
W. E. Carlos ◽  
M. E. Twigg ◽  
P. E. Thompson
Keyword(s):  
Depth Profile ◽  
Epr Spectra ◽  
Transmission Electron Micrograph ◽  
Dangling Bond ◽  
Electron Micrograph ◽  
Cross Sectional ◽  
Paramagnetic Resonance ◽  
Transmission Electron ◽  
Interfacial Defects ◽  
Electron Paramagnetic

AbstractThis paper reports etching results supporting the identification of the SG1 center as a germanium dangling bond defect at the interface between an oxide and crystalline SiGe. The presence of this defect is significant because, like an analogous center in Si-based systems, it may alter the operation of any microelectronic or micro-optical device which incorporates an interface between SiGe and an overlying oxide. The samples examined are oxygen implanted SiGe layers in which the SG 1 center is believed to occur at the interface between oxide precipitates and SiGe. Because of the center's apparent relation to the oxide precipitates distributed through layers of the sample, a depth profile assists in confirming the interfacial nature of the defect. We obtain a depth profile by comparing electron paramagnetic resonance (EPR) spectra of samples etched to decreasing thickness. EPR spectra indicate that the SG1 center decreases with depth in a manner that when correlated to a cross sectional transmission electron micrograph confirms the association with Si0 2 and supports its location at the SiGe/SiO2 precipitate interface.

High contrast at low dose using a single, defocussed transmission electron micrograph

Micron ◽  
2019 ◽  
Vol 124 ◽  
pp. 102701 ◽  
Author(s):  
L. Clark ◽  
T.C. Petersen ◽  
T. Williams ◽  
M.J. Morgan ◽  
D.M. Paganin ◽  
...  
Keyword(s):  
Low Dose ◽  
Transmission Electron Micrograph ◽  
High Contrast ◽  
Electron Micrograph ◽  
Transmission Electron

Mechanical Properties of Nanostructured Zirconia Coatings Fabricated by Air Plasma Spraying

2008 ◽  
Vol 368-372 ◽  
pp. 1280-1283 ◽  
Author(s):  
Hong Zhou ◽  
Jun Wang ◽  
Bo He ◽  
Fei Li ◽  
Jing Ma ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Rapid Development ◽  
Bimodal Distribution ◽  
Transmission Electron Micrograph ◽  
Air Plasma ◽  
Electron Micrograph ◽  
Air Plasma Spraying ◽  
Transmission Electron ◽  
Columnar Grains ◽  
Potential Applications

Nanostructured coatings are experiencing a rapid development in recent years due to their potential applications in a wide variety of technological areas. In order to improve the properties of thermal barrier coatings, nanostructured 8 wt% yttria partial stabilized zirconia coatings were deposited by air plasma spraying with reconstituted nanoparticles on titanium alloy substrates. For comparison, the conventional counterparts were also fabricated. Their microstructures were investigated by using transmission electron micrograph and scanning electron micrograph. Their mechanical behaviors were evaluated via Vickers microhardness test and tensile test. The results indicate that the nanostructured zirconia coatings with original nanostructure and columnar grains have higher microhardness and adhesive strength than the conventional counterparts. Both the nanostructured coating and the conventional coating exhibit a bimodal distribution of microhardness values, which are analyzed via Weibull statistics. This phenomenon is attributed to the presence of molten and non-molten parts in the coatings.

scholarly journals Oral Toxicity of Photorhabdusluminescens W14 Toxin Complexes inEscherichiacoli

2001 ◽  
Vol 67 (11) ◽  
pp. 5017-5024 ◽  
Author(s):  
Nicholas Waterfield ◽  
Andrea Dowling ◽  
Sadhana Sharma ◽  
Phillip J. Daborn ◽  
Ursula Potter ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Mode Of Action ◽  
Transmission Electron Micrograph ◽  
Gene Promoters ◽  
Electron Micrograph ◽  
Oral Toxicity ◽  
Transmission Electron ◽  
Toxin Complex ◽  
Potential Mode

ABSTRACT Previous attempts to express the toxin complex genes ofPhotorhabdus luminescens W14 inEscherichia coli have failed to reconstitute their oral toxicity to the model insectManduca sexta. Here we show that the combination of three genes, tcdA, tcdB, and tccC, is essential for oral toxicity toM. sexta when expression inE. coli is used. Further, when transcription from native toxin complex gene promoters is used, maximal toxicity in E. coli cultures is associated with the addition of mitomycin C to the growth medium. In contrast, the expression of tcdAB (or the homologoustcaABC operon) with no recombinant tccChomolog in a different P. luminescensstrain, K122, is sufficient to confer oral toxicity on this strain, which is otherwise not orally toxic. We therefore infer thatP. luminescens K122 carries a functionaltccC-like homolog within its own genome, a hypothesis supported by Southern analysis. Recombinant toxins from bothP. luminescens K122 and E.coli were purified as high-molecular-weight particulate preparations. Transmission electron micrograph (TEM) images of these particulate preparations showed that the expression oftcdAB (either with or without tccC) inE. coli produces visible ∼25-nm-long complexes with a head and tail-like substructure. These data are consistent with a model whereby TcdAB constitutes the majority of the complex visible under TEM and TccC either is a toxin itself or is an activator of the complex. The implications for the potential mode of action of the toxin complex genes are discussed.

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