scholarly journals Characterization of Thermally Annealed Sb Implanted Fused Silica

1993 ◽  
Vol 316 ◽  
Author(s):  
S.H. Morgan ◽  
Z. Pan ◽  
D.O. Henderson ◽  
S.Y. Park ◽  
R.A. Weeks ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Annealing Treatment ◽  
Local Environment ◽  
Fused Silica ◽  
Index Of Refraction ◽  
Oxide Glasses ◽  
Before And After ◽  
Nonlinear Index ◽  
Optical Behavior

ABSTRACTThe local environment of the polarizable ion in heavy metal oxide glasses is postulated to strongly influence the nonlinear response of these materials. We have previously observed that post-implantation thermal annealing changes the chemical properties of the implanted layer in a different fashion in Pb- and Bi- implanted SiO2. In this paper we report the optical behavior of Sb-implanted SiO2 as a function of annealing temperature and atmosphere. High purity fused silica substrates were implanted at room temperature to a dose of 6 × 1016 ions/cm2, and subsequently annealed at temperatures from 500 to 1000 C in argon and oxygen atmospheres. RBS, optical absorption (1.8 to 6.2 eV), infrared reflectance (450 to 5000 cm-1), and nonlinear index of refraction were measured before and after annealing. The results of these measurements indicate that annealing treatment significantly affects the local environment of the implanted Sb ions, and consequently the optical response.

Characterization of Cold-Sprayed FeAl/WC Nanocomposite Coating

2013 ◽  
Vol 423-426 ◽  
pp. 63-66
Author(s):  
Hong Tao Wang ◽  
Ruo Yu Wang ◽  
Xiao Chen ◽  
Xiao Bo Bai ◽  
Zeng Xiang Dong ◽  
...  
Keyword(s):  
Grain Size ◽  
Lamellar Structure ◽  
Annealing Temperature ◽  
Annealing Treatment ◽  
Cold Spraying ◽  
Nanocomposite Coating ◽  
Mechanically Alloyed ◽  
Dense Microstructure ◽  
Before And After

A FeAl/WC nanocomposite coating was produced by cold spraying of mechanically alloyed Fe/Al/WC composite powder assisted with annealing treatment. The microstructure and grain size of FeAl/WC nanocomposite coating before and after annealing treatment were characterized. The results indicated that as-sprayed Fe (Al)/WC nanocomposite coating presented a dense microstructure with lamellar structure. The phase transformation from Fe (Al) solid solution to FeAl intermetallics within as-sprayed nanocomposite coating occurred when annealed at 550°C for 25 h. The annealed nanocomposite coating was composed of nanograins of size ranging from 50-100 nm and the grain size of FeAl increased with increasing the annealing time. Moreover, the effect of annealing temperature on the microstructure of the FeAl/WC nanocomposite coating was investigated.

Structural characterization of Ti implanted AlN

1995 ◽  
Vol 10 (12) ◽  
pp. 3136-3142 ◽  
Author(s):  
M. Borowski ◽  
A. Traverse ◽  
J.P. Dallas
Keyword(s):  
Chemical Properties ◽  
Local Environment ◽  
Heat Of Formation ◽  
Implantation Process ◽  
Calculated Distribution ◽  
Final System ◽  
Post Implantation ◽  
Key Parameter

Sintered AlN ceramics were implanted by 1 × 1017 Ti/cm2 at an energy of 70 keV in order to investigate the role of the chemical properties of the implanted species on the phase formed during the implantation process. The implanted ions were found in a depth profile corresponding to the calculated distribution of the vacancies produced during the implantation process instead of the predicted ion profile. Identification of the local environment of Ti and of the resulting phase led us to conclude that Ti is surrounded by N after the collision cascade and forms TiN after post-implantation annealing. The TiN nucleus if formed by substitution of Al by Ti. Therefore, the heat of formation, which is more negative for TiN than for AlN, is found to be a key parameter to predict the final system.

scholarly journals Nonlinear index of refraction of Cu- and Pb-implanted fused silica

1992 ◽  
Vol 65 (1-4) ◽  
pp. 405-411 ◽  
Author(s):  
R.F. Haglund ◽  
R.H. Magruder ◽  
S.H. Morgan ◽  
D.O. Henderson ◽  
R.A. Weller ◽  
...  
Keyword(s):  
Fused Silica ◽  
Index Of Refraction ◽  
Nonlinear Index

An Electron Microscope Study of Interdiffusion and Compound Formation in Ta-Au Thin Films

1973 ◽  
Vol 31 ◽  
pp. 32-33 ◽  
Author(s):  
T. C. Tisone ◽  
S. Lau
Keyword(s):  
Electron Microscope ◽  
Electron Microscope Study ◽  
Thermally Grown Oxide ◽  
Ion Milling ◽  
Compound Formation ◽  
Technology Application ◽  
Transmission Electron ◽  
Before And After ◽  
Au Thin Films

In a study of the properties of a Ta-Au metallization system for thin film technology application, the interdiffusion between Ta(bcc)-Au, βTa-Au and Ta2M-Au films was studied. Considered here is a discussion of the use of the transmission electron microscope(TEM) in the identification of phases formed and characterization of the film microstructures before and after annealing.The films were deposited by sputtering onto silicon wafers with 5000 Å of thermally grown oxide. The film thicknesses were 2000 Å of Ta and 2000 Å of Au. Samples for TEM observation were prepared by ultrasonically cutting 3mm disks from the wafers. The disks were first chemically etched from the silicon side using a HNO3 :HF(19:5) solution followed by ion milling to perforation of the Au side.

TEM characterization of proton-exchanged LiNbO3 optical waveguides

1986 ◽  
Vol 44 ◽  
pp. 480-481
Author(s):  
W. E. Lee
Keyword(s):  
Refractive Index ◽  
Benzoic Acid ◽  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Lithium Ions ◽  
Wide Channel ◽  
Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

scholarly journals Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from Waters

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1757
Author(s):  
Yesica Vicente-Martínez ◽  
Manuel Caravaca ◽  
Antonio Soto-Meca ◽  
Miguel Ángel Martín-Pereira ◽  
María del Carmen García-Onsurbe
Keyword(s):  
Magnetic Nanoparticles ◽  
Nitrate Content ◽  
Adsorption Efficiency ◽  
Experimental Conditions ◽  
Dependent Behavior ◽  
Before And After ◽  
Naoh Solution ◽  
High Concentrations ◽  
Interference Studies

This paper presents a novel procedure for the treatment of contaminated water with high concentrations of nitrates, which are considered as one of the main causes of the eutrophication phenomena. For this purpose, magnetic nanoparticles functionalized with silver (Fe3O4@AgNPs) were synthesized and used as an adsorbent of nitrates. Experimental conditions, including the pH, adsorbent and adsorbate dose, temperature and contact time, were analyzed to obtain the highest adsorption efficiency for different concentration of nitrates in water. A maximum removal efficiency of 100% was reached for 2, 5, 10 and 50 mg/L of nitrate at pH = 5, room temperature, and 50, 100, 250 and 500 µL of Fe3O4@AgNPs, respectively. The characterization of the adsorbent, before and after adsorption, was performed by energy dispersive X-ray spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller analysis and Fourier-transform infrared spectroscopy. Nitrates can be desorbed, and the adsorbent can be reused using 500 µL of NaOH solution 0.01 M, remaining unchanged for the first three cycles, and exhibiting 90% adsorption efficiency after three regenerations. A deep study on equilibrium isotherms reveals a pH-dependent behavior, characterized by Langmuir and Freundlich models at pH = 5 and pH = 1, respectively. Thermodynamic studies were consistent with physicochemical adsorption for all experiments but showed a change from endothermic to exothermic behavior as the temperature increases. Interference studies of other ions commonly present in water were carried out, enabling this procedure as very selective for nitrate ions. In addition, the method was applied to real samples of seawater, showing its ability to eliminate the total nitrate content in eutrophized waters.

scholarly journals Assessment of Characteristics of Acid Mine Drainage Treated with Fly Ash

2021 ◽  
Vol 11 (9) ◽  
pp. 3910
Author(s):  
Saba Shirin ◽  
Aarif Jamal ◽  
Christina Emmanouil ◽  
Akhilesh Kumar Yadav
Keyword(s):  
Fly Ash ◽  
Acid Mine Drainage ◽  
Power Plants ◽  
Mine Drainage ◽  
Thermal Power ◽  
Mineralogical Characterization ◽  
Acid Mine ◽  
Before And After ◽  
Abandoned Coal Mines

Acid mine drainage (AMD) occurs naturally in abandoned coal mines, and it contains hazardous toxic elements in varying concentrations. In the present research, AMD samples collected from an abandoned mine were treated with fly ash samples from four thermal power plants in Singrauli Coalfield in the proximate area, at optimized concentrations. The AMD samples were analyzed for physicochemical parameters and metal content before and after fly ash treatment. Morphological, geochemical and mineralogical characterization of the fly ash was performed using SEM, XRF and XRD. This laboratory-scale investigation indicated that fly ash had appreciable neutralization potential, increasing AMD pH and decreasing elemental and sulfate concentrations. Therefore, fly ash may be effectively used for AMD neutralization, and its suitability for the management of coalfield AMD pits should be assessed further.

scholarly journals Single Step 2-Port Device De-Embedding Algorithm for Fixture-DUT-Fixture Network Assembly

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1275
Author(s):  
Simone Scafati ◽  
Enza Pellegrino ◽  
Francesco de Paulis ◽  
Carlo Olivieri ◽  
James Drewniak ◽  
...  
Keyword(s):  
Standard Technique ◽  
Single Step ◽  
Scattering Parameters ◽  
Linear Set ◽  
S Parameter ◽  
Parameter Conversion ◽  
Before And After ◽  
One Step ◽  
Typical Measurement

The de-embedding of measurement fixtures is relevant for an accurate experimental characterization of radio frequency and digital electronic devices. The standard technique consists in removing the effects of the measurement fixtures by the calculation of the transfer scattering parameters (T-parameters) from the available measured (or simulated) global scattering parameters (S-parameters). The standard de-embedding is achieved by a multiple steps process, involving the S-to-T and subsequent T-to-S parameter conversion. In a typical measurement setup, two fixtures are usually placed before and after the device under test (DUT) allowing the connection of the device to the calibrated vector network analyzer coaxial ports. An alternative method is proposed in this paper: it is based on the newly developed multi-network cascading algorithm. The matrices involved in the fixture-DUT-fixture cascading gives rise to a non-linear set of equations that is in one step analytically solved in closed form, obtaining a unique solution. The method is shown to be effective and at least as accurate as the standard multi-step de-embedding one.

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