scholarly journals Phase composition and concentration of yttriumin films during the deposition of aluminumand aluminum alloys from the gas phase

2021 ◽  
Vol 17 (4) ◽  
pp. 16-31
Author(s):  
Yury P. Snitovsky
Keyword(s):  
Gas Phase ◽  
Mass Fraction ◽  
Thermal Evaporation ◽  
Quantitative Metallography ◽  
Aluminum Films ◽  
Nanoelectronic Devices ◽  
Thin Aluminum ◽  
Alumina Particles ◽  
Before And After ◽  
Scanning Electron

The work is devoted to the study of the stabilizing effect of yttrium additions during the deposition of thin aluminum films, which are used for the manufacture of elements of micro- and nanoelectronic devices. The surfaces of Al films doped with aluminum oxide were investigated using a scanning electron microscope before and after annealing for 300420 s at a temperature of 500 C. It is shown that fine alumina particles are uniformly distributed on the surface of the films during thermal evaporation of a wire made of an Al Al2O3 alloy. By the method of quantitative metallography, the content of the AlxOy phase in the Al films was determined: when spraying wire from the Al Al2O3 alloy, its content was 1012% of the mass fraction; when spraying wire made of Al Al2O3 alloy and Al wire in a ratio of 50:50 1% mass fraction.

Detonation Chemistry Of Glycidyl Azide Polymer

1995 ◽  
Vol 418 ◽  
Author(s):  
Ping Ling ◽  
Jill Sakata ◽  
Charles A. Wight
Keyword(s):  
Laser Fluence ◽  
Molecular Nitrogen ◽  
Initial Step ◽  
Laser Vaporization ◽  
Initial Reaction ◽  
Glycidyl Azide Polymer ◽  
Aluminum Films ◽  
Thin Aluminum ◽  
Before And After ◽  
Glycidyl Azide

AbstractThe initial step of chemical reaction initiated by laser-generated shock waves has been observed in glycidyl azide polymer (GAP) in condensed phase. Shocks are generated by pulsed laser vaporization of thin aluminum films and launched into adjacent films of GAP at 77 K. Comparison of FIIR spectra obtained before and after shock passage shows that initial reaction involves elimination of molecular nitrogen from the azide functional groups of the polymer. The shock arrival time has been measured by a velocity interferometer as a function of thickness of GAP and laser fluence. The shock pressure has been calculated by using a universal liquid state Hugoniot. A simple model is proposed to calculate shock velocity and pressure as a function of laser fluence. The results are in agreement with experimental data.

The Effect of Tungsten on the Nucleation and Growth of thin Aluminum Alloy Films

1993 ◽  
Vol 317 ◽  
Author(s):  
Bea CAO ◽  
N. David Theodore ◽  
Hank Shin ◽  
Peter Fejes ◽  
Les Hendrickson
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Nucleation And Growth ◽  
Growth Behavior ◽  
Aluminum Films ◽  
Surface Energies ◽  
Transmission Electron ◽  
Thin Aluminum ◽  
Scanning Electron

ABSTRACTA variety of alloying elements are currently being investigated for their effects on the mechanical properties and reliability of thin aluminum films. In the present study, scanning electron microscopy and transmission electron microscopy are used to study the nucleation and growth of Al-1.5wt%Cu and Al-1.5wt% Cu-0.2wt% W films. Differences in Microstructure, nucleation and growth behavior are observed and are explained in terms of changes in surface energies and atomic Mobilities.

Synchrony of Digestion of SV40 DNA by Exonuclease III Determined by EM

1975 ◽  
Vol 33 ◽  
pp. 674-675
Author(s):  
Ray Wu ◽  
G. Ruben ◽  
B. Siegel ◽  
P. Spielman ◽  
E. Jay
Keyword(s):  
Dark Field ◽  
Uranyl Acetate ◽  
Enzyme Digestion ◽  
Dna Molecules ◽  
Exonuclease Iii ◽  
Aluminum Films ◽  
Double Stranded Dna ◽  
Before And After ◽  
Exo Iii ◽  
Sv40 Dna

A method for determining long nucleotide sequences of double-stranded DNA is being developed. It involves (a) the synchronous digestion of the DNA from the 3' ends with EL coli exonuclease III (Exo III) followed by (b) resynthesis with labeled nucleotides and DNA polymerase. A crucial factor in the success of this method is the degree to which the enzyme digestion proceeds synchronously under proper conditions of incubation (step a). Dark field EM is used to obtain accurate measurements on the lengths and distribution of the DNA molecules before and after digestion with Exo III, while gel electrophoresis is used in parallel to obtain a mean length for these molecules. It is the measurements on a large enough sample of individual molecules by EM that provides the information on how synchronously the digestion proceeds. For length measurements, the DNA molecules were picked up on 20-30 Å thick carbon-aluminum films, using the aqueous Kleinschmidt technique and stained with 7.5 x 10-5M uranyl acetate in 90% ethanol for 3 minutes.

Investigation of Adsorption Effect of Carbon Monoxide on Coniine: A DFT Study

2021 ◽  
Vol 17 ◽  
Author(s):  
Siyamak Shahab ◽  
Masoome Sheikhi ◽  
Mehrnoosh Khaleghian ◽  
Marina Murashko ◽  
Mahin Ahmadianarog ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Density Functional ◽  
Energy Gap ◽  
Adsorption Effect ◽  
Chemical Shift Tensors ◽  
Solvent Water ◽  
Donor And Acceptor ◽  
Before And After ◽  
Electron Donor And Acceptor

: For the first time in the present study, the non-bonded interaction of the Coniine (C8H17N) with carbon monoxide (CO) was investigated by density functional theory (DFT/M062X/6-311+G*) in the gas phase and solvent water. The adsorption of the CO over C8H17N was affected on the electronic properties such as EHOMO, ELUMO, the energy gap between LUMO and HOMO, global hardness. Furthermore, chemical shift tensors and natural charge of the C8H17N and complex C8H17N/CO were determined and discussed. According to the natural bond orbital (NBO) results, the molecule C8H17N and CO play as both electron donor and acceptor at the complex C8H17N/CO in the gas phase and solvent water. On the other hand, the charge transfer is occurred between the bonding, antibonding or nonbonding orbitals in two molecules C8H17N and CO. We have also investigated the charge distribution for the complex C8H17N/CO by molecular electrostatic potential (MEP) calculations using the M062X/6-311+G* level of theory. The electronic spectra of the C8H17N and complex C8H17N/CO were calculated by time dependent DFT (TD-DFT) for investigation of the maximum wavelength value of the C8H17N before and after the non-bonded interaction with the CO in the gas phase and solvent water. Therefore, C8H17N can be used as strong absorbers for air purification and reduce environmental pollution.

Time-Resolved, Laser-Induced Phase Transformation in Aluminum

1984 ◽  
Vol 35 ◽  
Author(s):  
S. Williamson ◽  
G. Mourou ◽  
J.C.M. Li
Keyword(s):  
Point Defect ◽  
Long Range ◽  
Rapid Heating ◽  
Range Order ◽  
Nucleation Theory ◽  
Long Range Order ◽  
Time Resolved ◽  
Aluminum Films ◽  
Thin Aluminum ◽  
Initial Nucleus

ABSTRACTThe technique of picosecond electron diffraction is used to time resolve the laser-induced melting of thin aluminum films. It is observed that under rapid heating conditions, the long range order of the lattice subsists for lattice temperatures well above the equilibrium point, indicative of superheating. This superheating can be verified by directly measuring the lattice temperature. The collapse time of the long range order is measured and found to vary from 20 ps to several nanoseconds according to the degree of superheating. Two interpretations of the delayed melting are offered, based on the conventional nucleation and point defect theories. While the nucleation theory provides an initial nucleus size and concentration for melting to occur, the point defect theory offers a possible explanation for how the nuclei are originally formed.

scholarly journals Redox Mechanism of Azathioprine and Its Interaction with DNA

2021 ◽  
Vol 22 (13) ◽  
pp. 6805
Author(s):  
Mihaela-Cristina Bunea ◽  
Victor-Constantin Diculescu ◽  
Monica Enculescu ◽  
Horia Iovu ◽  
Teodor Adrian Enache
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Scanning Electron Microscopy ◽  
Structural Changes ◽  
Differential Pulse ◽  
Immunosuppressive Drug ◽  
Redox Mechanism ◽  
Before And After ◽  
Dna Film ◽  
Scanning Electron

The electrochemical behavior and the interaction of the immunosuppressive drug azathioprine (AZA) with deoxyribonucleic acid (DNA) were investigated using voltammetric techniques, mass spectrometry (MS), and scanning electron microscopy (SEM). The redox mechanism of AZA on glassy carbon (GC) was investigated using cyclic and differential pulse (DP) voltammetry. It was proven that the electroactive center of AZA is the nitro group and its reduction mechanism is a diffusion-controlled process, which occurs in consecutive steps with formation of electroactive products and involves the transfer of electrons and protons. A redox mechanism was proposed and the interaction of AZA with DNA was also investigated. Morphological characterization of the DNA film on the electrode surface before and after interaction with AZA was performed using scanning electron microscopy. An electrochemical DNA biosensor was employed to study the interactions between AZA and DNA with different concentrations, incubation times, and applied potential values. It was shown that the reduction of AZA molecules bound to the DNA layer induces structural changes of the DNA double strands and oxidative damage, which were recognized through the occurrence of the 8-oxo-deoxyguanosine oxidation peak. Mass spectrometry investigation of the DNA film before and after interaction with AZA also demonstrated the formation of AZA adducts with purine bases.

Analysis of surface conditioning methods on core-veneer bond strength of CAD/CAM zirconia restorations

2020 ◽  
pp. 1-11
Author(s):  
Anip K. Roy ◽  
Govind N. Prasad ◽  
Tushar V. Bhagat ◽  
Saurabh Chaturvedi ◽  
Vishwanath Gurumurthy ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Group Iv ◽  
Control Group ◽  
Group Iii ◽  
Surface Conditioning ◽  
Group I ◽  
Alumina Particles ◽  
Scanning Electron

BACKGROUND: The increased strength of zirconia has resulted in its widespread application in clinical dentistry. Nevertheless, the fracture of veneering porcelains remains one of the key reasons of failure. OBJECTIVE: The objective of this study was to compare and analyze the influence of surface conditioning methods on the core-veneer bond strength of zirconia restorations. METHODS: Thirty specimens of zirconia core with sizes 10 × 5 × 5 mm were layered with porcelain of sizes 5 × 3 × 3 mm. On the basis of different surface conditioning methods, four groups were made: Group I: abrasion with airborne alumina particles of 110 μm size, Group II: sandblasting with silica coated alumina particles of 50 μm in size, Group III (modified group): alteration with a coating of zirconia powder prior to sintering, and Group IV (control group): metal core specimens. The shear force of all specimens was tested using a universal testing machine with a 0.5 mm/min crosshead speed. One-way analysis of variance (ANOVA) and Tukey’s post hoc pair wise comparison (p= 0.05) were performed to analyze the shear bond strength. A scanning electron microscope was used to assess the fractured specimens. RESULTS: A statistically significant difference was noted between the groups. The mean value of shear bond strength was 40.25 MPa for Group I, 41.93 MPa for Group II, 48.08 MPa for Group III and 47.01 MPa for Group IV. CONCLUSIONS: The modified zirconia group and control group demonstrated a significantly higher mean bond strength than that of Group I, where airborne particle abrasion was used. The scanning electron microscope showed that cohesive fracture in the porcelain veneers was the main problem of failure in altered zirconia. The modified zirconia specimens in Group III demonstrated significantly improved values of shear bond strength.

scholarly journals Cementitious Composites Reinforced with Polypropylene, Nylon and Polyacrylonitile Fibres

2012 ◽  
Vol 730-732 ◽  
pp. 271-276
Author(s):  
H.R. Pakravan ◽  
M. Jamshidi ◽  
M. Latifi ◽  
F. Pacheco-Torgal
Keyword(s):  
Absorption Capacity ◽  
Cement Matrix ◽  
Cementitious Composites ◽  
Scanning Electron Micrographs ◽  
Energy Absorption Capacity ◽  
Cement Ratio ◽  
Pull Out ◽  
Water To Cement Ratio ◽  
Before And After ◽  
Scanning Electron

This paper compares the adhesion strength between three polymeric fibres (polypropylene (PP), nylon66 (N66) and polyacrylonitrile (PAN)) embedded in a cement paste. The specimens were prepared at a water to cement ratio (w/c) of 0.5 and tested after 7, 14 and 28 curing days. It was found that although the adhesion between the polymeric fibres to the cement matrix is an important factor, the energy absorption capacity or energy dissipation ability of the fibres, plays a more important role in the improvement of the cementitious composites fracture toughness. Scanning electron micrographs were used to characterize the fibres surface before and after the Pull-out tests.

scholarly journals Superlayer Residual Stress Effect on the Indentation Adhesion Measurements

1999 ◽  
Vol 594 ◽  
Author(s):  
Alex A. Volinsky ◽  
Neville R. Moody ◽  
William W. Gerberich
Keyword(s):  
Residual Stress ◽  
Sputter Deposition ◽  
Work Of Adhesion ◽  
Stress Effect ◽  
Aluminum Films ◽  
Nanoindentation Testing ◽  
Deposition Parameters ◽  
Thin Aluminum ◽  
Residual Stress Effect ◽  
Sputter Deposited

AbstractThe practical work of adhesion has been measured in thin aluminum films as a function of film thickness and residual stress. These films were sputter deposited onto thermally oxidized silicon wafers followed by sputter deposition of a one micron thick W superlayer. The superlayer deposition parameters were controlled to produce either a compressive residual stress of 1 GPa or a tensile residual stress of 100 MPa. Nanoindentation testing was then used to induce delamination and a mechanics based model for circular blister formation was used to determine practical works of adhesion. The resulting measured works of adhesion for all films between 100 nm and 1 μm thick was 30 J/m2 regardless of superlayer stress. However, films with the compressively stressed superlayers produced larger blisters than films with tensile stressed superlayers. In addition, these films were susceptible to radial cracking producing a high variability in average adhesion values.

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