ORIGIN OF ORDERING OSCILLATION OF LOCAL COMPOSITION IN MELT-PROCESSED REBa2Cu3O7-δ SUPERCONDUCTORS (RE: Sm, Eu, Gd)

2005 ◽  
Vol 19 (01n03) ◽  
pp. 159-161
Author(s):  
A. HU ◽  
N. SAKAI ◽  
I. HIRABAYASHI ◽  
M. WINTER ◽  
M. R. KOBLISCHKA ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Superconducting Transition ◽  
High Quality ◽  
Local Composition ◽  
Pinning Centers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Novel Structure ◽  
Transmission Electron ◽  
Field Dependent

High quality melt-processed ( Sm 0.33 Eu 0.33 Gd 0.33) Ba 2 Cu 3 O 7-δ superconductors were grown and microstructural origin of their distinguished superconducting performance was investigated by atomic force microscopy (AFM), transmission electron microscopy (TEM) and the field dependent superconducting transition performed with SQUID. A nanoscopic periodic array of chemical composition was unveiled. This novel structure acted as δTc-style pinning centers.

IMPROVED CHEMICAL SYNTHESIS OF GRAPHENE USING A SAFER SOLVOTHERMAL ROUTE

2011 ◽  
Vol 10 (01n02) ◽  
pp. 39-42 ◽  
Author(s):  
DILIP KUMAR SINGH ◽  
P. K. IYER ◽  
P. K. GIRI
Keyword(s):  
Electron Microscopy ◽  
Graphene Sheets ◽  
Pyrolysis Process ◽  
High Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Afm Analysis ◽  
Bulk Production

Graphene has been synthesized using thermal decomposition of ethyl alcohol in a medium pressure autoclave. The synthesis was carried out in the presence of strong alkaline solution at a temperature of ~230°C and pressure of 60 bar. The as-synthesized graphene has been characterized using atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM). AFM analysis on various graphene sheets shows the presence of monolayer (n = 1) to trilayer (n = 3) graphene sheets with thickness of ~1.168 nm. HRTEM studies confirm the high quality of graphene obtained after purification of as-synthesized product. Use of chemically nonexplosive material for synthesis and reduced reaction time along with the absence of post-pyrolysis process make it a commercially viable process for bulk production of graphene.

Epitaxial Growth of Nb Films and Nb/Cu Bilayers on A12O3 Substrates by DC Magnetron Sputtering

1998 ◽  
Vol 528 ◽  
Author(s):  
R. Loloee ◽  
M.A. Crimp ◽  
W. Zhu ◽  
W.P. Pratt
Keyword(s):  
Electron Microscopy ◽  
Sputter Deposition ◽  
Dc Magnetron Sputtering ◽  
High Quality ◽  
Cu Films ◽  
Force Microscopy ◽  
Sputtered Films ◽  
Sapphire Substrates ◽  
Atomic Force ◽  
Transmission Electron

AbstractEpitaxial single crystal Nb films have been grown by sputter deposition on (1 1 2 0) sapphire substrates. Subsequently, high quality epitaxial Cu films, with two orientation variants, have been grown onto the epitaxial Nb films. The sputtered films have been characterized using atomic force microscopy, electron backscattered patterns, and conventional transmission electron microscopy.

Defect-Engineered Graded GexSi1-x Buffers on Si (001) with Extreme Low Threading Dislocation Density

1995 ◽  
Vol 378 ◽  
Author(s):  
G. Kissinger ◽  
T. Morgenstern ◽  
G. Morgenstern ◽  
H. B. Erzgräber ◽  
H. Richter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Threading Dislocation Density

AbstractStepwise equilibrated graded GexSii-x (x≤0.2) buffers with threading dislocation densities between 102 and 103 cm−2 on the whole area of 4 inch silicon wafers were grown and studied by transmission electron microscopy, defect etching, atomic force microscopy and photoluminescence spectroscopy.

Effectiveness and Reliability of Metal Diffusion Barriers for Copper Interconnects

1995 ◽  
Vol 403 ◽  
Author(s):  
G. Bai ◽  
S. Wittenbrock ◽  
V. Ochoa ◽  
R. Villasol ◽  
C. Chiang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Chemical Vapor ◽  
Diffusion Barriers ◽  
Copper Interconnects ◽  
Time To Failure ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

AbstractCu has two advantages over Al for sub-quarter micron interconnect application: (1) higher conductivity and (2) improved electromigration reliability. However, Cu diffuses quickly in SiO2and Si, and must be encapsulated. Polycrystalline films of Physical Vapor Deposition (PVD) Ta, W, Mo, TiN, and Metal-Organo Chemical Vapor Deposition (MOCVD) TiN and Ti-Si-N have been evaluated as Cu diffusion barriers using electrically biased-thermal-stressing tests. Barrier effectiveness of these thin films were correlated with their physical properties from Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), Secondary Electron Microscopy (SEM), and Auger Electron Spectroscopy (AES) analysis. The barrier failure is dominated by “micro-defects” in the barrier film that serve as easy pathways for Cu diffusion. An ideal barrier system should be free of such micro-defects (e.g., amorphous Ti-Si-N and annealed Ta). The median-time-to-failure (MTTF) of a Ta barrier (30 nm) has been measured at different bias electrical fields and stressing temperatures, and the extrapolated MTTF of such a barrier is > 100 year at an operating condition of 200C and 0.1 MV/cm.

Development of Ge Nanoparticles Embedded in GeO2 Matrix

2008 ◽  
Vol 8 (8) ◽  
pp. 4081-4085 ◽  
Author(s):  
Y. Batra ◽  
D. Kabiraj ◽  
D. Kanjilal
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Spectroscopic Studies ◽  
Electron Beam Evaporation ◽  
Granular Structure ◽  
Raman Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Ge Nanocrystals

Germanium (Ge) nanoparticles have attracted a lot of attention due to their excellent optical properties. In this paper, we report on the formation of Ge nanoparticles embedded in GeO2 matrix prepared by electron beam evaporation and subsequent annealing. Transmission electron microscopy (TEM) studies clearly indicate the formation of Ge nanocrystals in the films annealed at 500 °C. Fourier transform infrared (FTIR) spectroscopic studies are carried out to verify the evolution of the structure after annealingat each stage. Micro-Raman analysis also confirms the formation of Ge nanoparticles in the annealed films. Development of Ge nanoparticles is also established by photoluminescence (PL) analysis. Surface morphology study is carried out by atomic force microscopy (AFM). It shows the evolution of granular structure of the films with increasing annealing temperature.

scholarly journals Measuring the Autocorrelation Function of Nanoscale Three-Dimensional Density Distribution in Individual Cells Using Scanning Transmission Electron Microscopy, Atomic Force Microscopy, and a New Deconvolution Algorithm

2017 ◽  
Vol 23 (3) ◽  
pp. 661-667 ◽  
Author(s):  
Yue Li ◽  
Di Zhang ◽  
Ilker Capoglu ◽  
Karl A. Hujsak ◽  
Dhwanil Damania ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Density Distribution ◽  
Scanning Transmission Electron Microscopy ◽  
Mass Density ◽  
Three Dimensional ◽  
Force Microscopy ◽  
Statistical Measures ◽  
Atomic Force ◽  
Transmission Electron ◽  
Scanning Transmission

AbstractEssentially all biological processes are highly dependent on the nanoscale architecture of the cellular components where these processes take place. Statistical measures, such as the autocorrelation function (ACF) of the three-dimensional (3D) mass–density distribution, are widely used to characterize cellular nanostructure. However, conventional methods of reconstruction of the deterministic 3D mass–density distribution, from which these statistical measures can be calculated, have been inadequate for thick biological structures, such as whole cells, due to the conflict between the need for nanoscale resolution and its inverse relationship with thickness after conventional tomographic reconstruction. To tackle the problem, we have developed a robust method to calculate the ACF of the 3D mass–density distribution without tomography. Assuming the biological mass distribution is isotropic, our method allows for accurate statistical characterization of the 3D mass–density distribution by ACF with two data sets: a single projection image by scanning transmission electron microscopy and a thickness map by atomic force microscopy. Here we present validation of the ACF reconstruction algorithm, as well as its application to calculate the statistics of the 3D distribution of mass–density in a region containing the nucleus of an entire mammalian cell. This method may provide important insights into architectural changes that accompany cellular processes.

Ball-Milling Graphite Used for Synthesis of Biocompatible Blue Luminescent Graphene Quantum Dots

2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Zhou J ◽  
◽  
Dong Y ◽  
Ma Y ◽  
Zhang T ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ball Milling ◽  
Graphene Quantum Dots ◽  
Raw Material ◽  
Hydroxyl Groups ◽  
High Quality ◽  
Widespread Application ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Graphene Quantum Dots (GQDs) have been prepared by oxidationhydrothermal reaction, using ball-milling graphite as the starting materials. The prepared GQDs are endowed with excellent luminescence properties, with the optimum emission of 320nm. Blue photoluminescent emitted from the GQDs under ultraviolet light. The GQDs are ~3nm in width and 0.5~2 nm in thickness, revealed by high-resolution transmission electron microscopy and atomic force microscopy. In addition, Fourier transform infrared spectrum evidences the existence of carbonyl and hydroxyl groups, meaning GQDs can be dispersed in water easily and used in cellar imaging, and blue area inside L929 cells were clearly observed under the fluorescence microscope. Both low price of raw material and simple prepared method contribute to the high quality GQDs widespread application in future.

scholarly journals Spore Coat Architecture of Clostridium novyi NT Spores

2007 ◽  
Vol 189 (17) ◽  
pp. 6457-6468 ◽  
Author(s):  
Marco Plomp ◽  
J. Michael McCaffery ◽  
Ian Cheong ◽  
Xin Huang ◽  
Chetan Bettegowda ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Anaerobic Bacterium ◽  
Amorphous Layer ◽  
Spore Coat ◽  
Experimental Animals ◽  
Force Microscopy ◽  
Atomic Force ◽  
Clostridium Novyi ◽  
Transmission Electron

ABSTRACT Spores of the anaerobic bacterium Clostridium novyi NT are able to germinate in and destroy hypoxic regions of tumors in experimental animals. Future progress in this area will benefit from a better understanding of the germination and outgrowth processes that are essential for the tumorilytic properties of these spores. Toward this end, we have used both transmission electron microscopy and atomic force microscopy to determine the structure of both dormant and germinating spores. We found that the spores are surrounded by an amorphous layer intertwined with honeycomb parasporal layers. Moreover, the spore coat layers had apparently self-assembled, and this assembly was likely to be governed by crystal growth principles. During germination and outgrowth, the honeycomb layers, as well as the underlying spore coat and undercoat layers, sequentially dissolved until the vegetative cell was released. In addition to their implications for understanding the biology of C. novyi NT, these studies document the presence of proteinaceous growth spirals in a biological organism.

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