Preparation of TEM Sections using Natural Lithography

1990 ◽  
Vol 199 ◽  
Author(s):  
H. W. Deckman ◽  
J. H. Dunsmuir
Keyword(s):  
Colloidal Particles ◽  
Chemical Properties ◽  
Amorphous Semiconductor ◽  
Semiconductor Superlattices ◽  
Statistical Characterization ◽  
Metal Chalcogenide ◽  
Sample Structure ◽  
Layered Transition Metal ◽  
And Chemical Properties

ABSTRACTWe have developed and used a simple lithographic technique that allows preparation of TEM sections from a variety of materials in 10–45 minutes. To obtain TEM sections, 50–5,000 Å diameter cylindrical post structures are microfabricated on the surface of the sample using colloidal particles as an etch mask. The technique simultaneously prepares 104 – 108 posts. This not only allows a statistical characterization of sample structure but also provides enough material for studies of the electronic, spectroscopic and chemical properties of edge sites exposed on the post surfaces. These lithographically prepared posts have been used to study the structure of materials as diverse as a layered transition metal chalcogenide catalysts, semi-insulating polysilicon, amorphous semiconductor superlattices, crystalline metallic and semiconductor superlattices, and molecular-scale microporous superlattices.

Defect engineering of molybdenum disulfide for energy storage

2021 ◽  
Author(s):  
Zefang Yang ◽  
Lin Zhu ◽  
Chao-Nan Lv ◽  
Rui Zhang ◽  
Hai-Yan Wang ◽  
...  
Keyword(s):  
Molybdenum Disulfide ◽  
Chemical Properties ◽  
High Energy ◽  
High Energy Density ◽  
Physical And Chemical Properties ◽  
Defect Engineering ◽  
Metal Chalcogenide ◽  
Layered Transition Metal ◽  
Physical And Chemical ◽  
And Chemical Properties

Molybdenum disulfide, a typically layered transition metal chalcogenide, is considered one of the promising electrode candidates for next-generation high energy density batteries owing to its tunable physical and chemical properties,...

scholarly journals The effect of microstructural features on the mechanical properties of LZSA glass-ceramic matrix composites

Cerâmica ◽  
2013 ◽  
Vol 59 (351) ◽  
pp. 351-359 ◽  
Author(s):  
F. M. Bertan ◽  
A. P. Novaes de Oliveira ◽  
O. R. K. Montedo ◽  
D. Hotza ◽  
C. R. Rambo
Keyword(s):  
Glass Ceramic ◽  
Bending Strength ◽  
Chemical Properties ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Linear Shrinkage ◽  
Matrix Composites ◽  
Particulate Reinforced ◽  
And Chemical Properties

This work reports on the characterization of ZrSiO4 particulate-reinforced Li2O-ZrO2-SiO2-Al2O3 (LZSA) glass-ceramic matrix composites. The typical physical/mechanical and chemical properties of the glass batches and the composites were measured. A composition with 60 wt.% ZrSiO4 was preliminarily selected because it demonstrated the highest values of bending strength (190 MPa) and deep abrasion resistance (51 mm³). To this same composition was given a 7 wt.% bentonite addition in order to obtain plasticity behavior suitable for extrusion. The sintered samples (1150 ºC for 10 min) presented a thermal linear shrinkage of 14% and bending strength values of 220 MPa.

Infrared Characterization of PMMA-SiO2 Hybrid Glasses Obtained by Sol-Gel Process

2010 ◽  
Vol 1278 ◽  
Author(s):  
L.L. Díaz-Flores ◽  
A. S. López Rodríguez ◽  
P. SifuentesGallardo ◽  
M.A. Hernàndez Rivera ◽  
M.a Garnica Romo ◽  
...  
Keyword(s):  
Sol Gel ◽  
Chemical Properties ◽  
Hybrid Coatings ◽  
Force Microscopy ◽  
Air Atmosphere ◽  
Atomic Force ◽  
Sol Gel Process ◽  
Traditional Process ◽  
And Chemical Properties

AbstractThis work is about the production of hybrid coatings of the system SiO2-PMMA (PMMA, polymethylmethacrylate). These materials have interesting mechanical and chemical properties useful for anticorrosive and wear resistance applications. SiO2-PMMA hybrids were obtained by the sol-gel traditional process, using tetraethylorthosilicate (TEOS) and methylmethacrylate (MMA) by Aldrich Co, as starting reagents. The SiO2:PMMA ratio was varied from 0:1 to about 1:1 at air atmosphere deposition. The coatings were obtained on acrylic sheets and silicon wafers. A diversity of coatings with chemical composition ranging from SiO2 and PMMA to obtain the SiO2-PMMA hybrids were obtained. Infrared (IR) and atomic force microscopy (AFM), were performed to determinate structural and morphological behavior.

scholarly journals AVALIAÇÃO DA ESTRUTURA ELETRÔNICA DA FASE MONOCLINICA DO ÓXIDO DE NIÓBIO COM BASE NO USO DE DIFERENTES FUNCIONAIS DE DENSIDADE

Química Nova ◽  
2021 ◽  
Author(s):  
Kamila Ody ◽  
João Jesus ◽  
Carlos Cava ◽  
Anderson Albuquerque ◽  
Ary Maia ◽  
...  
Keyword(s):  
Density Functional ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Density Functionals ◽  
Monoclinic Structure ◽  
Functional Theory ◽  
Periodic Models ◽  
Physical And Chemical ◽  
And Chemical Properties

ASSESSMENT OF THE ELECTRONIC STRUCTURE OF THE MONOCLINIC PHASE OF NIOBIUM OXIDE BASED ON THE USE OF DIFFERENT DENSITY FUNCTIONALS. Niobium oxides, Nb2O5, are considered semiconductor materials with very attractive physical and chemical properties for applications in many areas, such as catalysis, sensors, medical, aerospace, etc. Especially, the characterization of Nb2O5-based nanostructures with monoclinic structure has received much attention in recent years. However, despite the great importance of this system, some of its fundamentals properties are still not fully understood. Hence, this work aims to apply the theoretical methodologies through Density Functional Theory (DFT) calculations in periodic models based on the use of different density functionals (like B1WC, B3PW, B3LYP, PBE0, PBESOL0, SOGGAXC, and WC1LYP) to investigate the physical and chemical properties of the monoclinic structure of Nb2O5. The band structures, energy bandgap, density of state, and vibrational properties, as well as order-disorder effects on the monoclinic structure of Nb2O5 are investigated in this study. Our theoretical results show a better agreement with experimental data for the B3LYP functional and hence lead to new perspectives on the deeper physicochemical understanding of the monoclinic Nb2O5. From these computational tools, it is possible to unravel the relations between structure and properties, which may contribute to the future development of new devices and applications based on these materials.

scholarly journals Characterization of gelatins from Nile tilapia skins preserved by freezing and salting

2019 ◽  
Vol 40 (6) ◽  
pp. 2581
Author(s):  
Adriana Cristina Bordignon ◽  
Maria Luiza Rodrigues de Souza ◽  
Eliane Gasparino ◽  
Edson Minoru Yajima ◽  
Jesuí Vergílio Visentainer ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Nile Tilapia ◽  
Saturated Fatty Acids ◽  
Chemical Properties ◽  
Monounsaturated Fatty Acids ◽  
Gel Strength ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

After Nile tilapia skin was preserved using the methods of freezing and dry salting, characteristics of skin gelatin were evaluated with regard to yield, rheological features and physical and chemical properties. Preservation was performed after filleting, at which time skins were either frozen (-18°C) for 7 days or salted (25°C) for 7 days. Although no differences (p > 0.05) were observed with respect to humidity, protein, lipid, ash and calcium levels, gelatin from salted skins had a higher concentration of iron relative to frozen skins. Further, twenty-three fatty acids were detected in salted skins compared with merely three found in skin derived gelatin. Of amino acids found, glycine, alanine, proline and arginine were the most abundant. Hydroxyproline abundance in salted and frozen skin gelatin were 8.76% and 8.71%, respectively. In addition, salted skin gelatins had a greater accumulation of saturated fatty acids and lower rates of monounsaturated fatty acids. Salted skin gelatin had the highest yield (18g × 100g-1), gel strength (200 g) and viscosity (19.02mPas) when compared to the yield (17g × 100g-1), gel strength (12.7g) and viscosity (9.16 mPas) of frozen skins. Results show that gelatin from dry salted skin had the best yield and also had relatively better rheological properties, more iron, and better coloration relative to gelatin obtained from frozen skins of Nile tilapia.

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