You limited your search to:

  Partner: UNT Libraries
 Collection: UNT Theses and Dissertations
Electrodeposition of Copper on Ruthenium Oxides and Bimetallic Corrosion of Copper/Ruthenium in Polyphenolic Antioxidants

Electrodeposition of Copper on Ruthenium Oxides and Bimetallic Corrosion of Copper/Ruthenium in Polyphenolic Antioxidants

Date: August 2007
Creator: Venkataraman, Shyam S.
Description: Copper (Cu) electrodeposition on ruthenium (Ru) oxides was studied due to important implications in semiconductor industry. Ruthenium, proposed as the copper diffusion barrier/liner material, has higher oxygen affinity to form different oxides. Three different oxides (the native oxide, reversible oxide, and irreversible oxide) were studied. Native oxide can be formed on exposing Ru in atmosphere. The reversible and irreversible oxides can be formed by applying electrochemical potential. Investigation of Cu under potential deposition on these oxides indicates the similarity between native and reversible oxides by its nature of inhibiting Cu deposition. Irreversible oxide formed on Ru surface is rather conductive and interfacial binding between Cu and Ru is greatly enhanced. After deposition, bimetallic corrosion of Cu/Ru in different polyphenols was studied. Polyphenols are widely used as antioxidants in post chemical mechanical planarization (CMP). For this purpose, different trihydroxyl substituted benzenes were used as antioxidants. Ru, with its noble nature enhances bimetallic corrosion of Cu. Gallic acid (3,4,5 - trihydroxybenzoic acid) was chosen as model compound. A mechanism has been proposed and validity of the mechanism was checked with other antioxidants. Results show that understanding the chemical structure of antioxidants is necessary during its course of reaction with Cu.
Contributing Partner: UNT Libraries
Electrodeposition of Diamond-like Carbon Films

Electrodeposition of Diamond-like Carbon Films

Date: August 2002
Creator: Chen, Minhua
Description: Electrodeposition of diamond-like carbon (DLC) films was studied on different substrates using two different electrochemical methods. The first electrochemical method using a three-electrode system was studied to successfully deposit hydrogenated DLC films on Nickel, Copper and Brass substrates. The as-deposited films were characterized by scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR) and cyclic voltammetry (CV). A variety of experimental parameters were shown to affect the deposition process. The second electrochemical method was developed for the first time to deposit hydrogen free DLC films on Ni substrates through a two-electrode system. The as-deposited films were characterized by Raman spectroscopy and FTIR. According to Raman spectra, a high fraction of diamond nanocrystals were found to form in the films. Several possible mechanisms were discussed for each deposition method. An electrochemical method was proposed to deposit boron-doped diamond films for future work.
Contributing Partner: UNT Libraries
Electrodeposition of Nickel and Nickel Alloy Coatings with Layered Silicates for Enhanced Corrosion Resistance and Mechanical Properties

Electrodeposition of Nickel and Nickel Alloy Coatings with Layered Silicates for Enhanced Corrosion Resistance and Mechanical Properties

Access: Use of this item is restricted to the UNT Community.
Date: August 2014
Creator: Tientong, Jeerapan
Description: The new nickel/layered silicate nanocomposites were electrodeposited from different pHs to study the influence on the metal ions/layered silicate plating solution and on the properties of the deposited films. Nickel/layered silicate nanocomposites were fabricated from citrate bath atacidic pHs (1.6−3.0), from Watts’ type solution (pH ~4-5), and from citrate bath at basic pH (~9). Additionally, the new nickel/molybdenum/layered silicate nanocomposites were electrodeposited from citrate bath at pH 9.5. The silicate, montmorillonite (MMT), was exfoliated by stirring in aqueous solution over 24 hours. The plating solutions were analyzed for zeta potential, particle size, viscosity, and conductivity to investigate the effects of the composition at various pHs. The preferred crystalline orientation and the crystalline size of nickel, nickel/layered silicate, nickel/molybdenum, and nickel/molybdenum/layered silicate films were examined by X-ray diffraction. The microstructure of the coatings and the surface roughness was investigated by scanning electron microscopy and atomic force microscopy. Nickel/molybdenum/layered silicate nanocomposites containing low content of layered silicate (1.0 g/L) had increase 32 % hardness and 22 % Young’s modulus values over the pure nickel/molybdenum alloy films. The potentiodynamic polarization and electrochemical impedance measurements showed that the nickel/molybdenum/layered silicate nanocomposite layers have higher corrosion resistance in 3.5% NaCl compared to the pure alloy ...
Contributing Partner: UNT Libraries
The Electrodeposition of Zinc

The Electrodeposition of Zinc

Date: August 1939
Creator: Flanagin, Charles E.
Description: This thesis examines the use of zinc for electroplating and compares its use to other metals. Experiments conducted to gather data indicated circumstances which resulted in optimal results.
Contributing Partner: UNT Libraries
Electrodepostion of Iron Oxide on Steel Fiber for Improved Pullout Strength in Concrete

Electrodepostion of Iron Oxide on Steel Fiber for Improved Pullout Strength in Concrete

Date: August 2014
Creator: Liu, Chuangwei
Description: Fiber-reinforced concrete (FRC) is nowadays extensively used in civil engineering throughout the world due to the composites of FRC can improve the toughness, flexural strength, tensile strength, and impact strength as well as the failure mode of the concrete. It is an easy crazed material compared to others materials in civil engineering. Concrete, like glass, is brittle, and hence has a low tensile strength and shear capacity. At present, there are different materials that have been employed to reinforce concrete. In our experiment, nanostructures iron oxide was prepared by electrodepostion in an electrolyte containing 0.2 mol/L sodium acetate (CH3COONa), 0.01 mol/L sodium sulfate (Na2SO4) and 0.01 mol/L ammonium ferrous sulfate (NH4)2Fe(SO4)2.6H2O under magnetic stirring. The resulted showed that pristine Fe2O3 particles, Fe2O3 nanorods and nanosheets were synthesized under current intensity of 1, 3, 5 mA, respectively. And the pull-out tests were performed by Autograph AGS-X Series. It is discovering that the load force potential of nanostructure fibers is almost 2 times as strong as the control sample.
Contributing Partner: UNT Libraries
Electroencephalographic (EEG) biofeedback treatment for children with attention deficit disorders in a school setting.

Electroencephalographic (EEG) biofeedback treatment for children with attention deficit disorders in a school setting.

Access: Use of this item is restricted to the UNT Community.
Date: December 2001
Creator: Mosse, Leah Kathryn
Description: The purpose of this study was to explore the use of EEG biofeedback in a school setting to assist students who had attentional challenges. The equipment for implementing biofeedback was relatively inexpensive and was easily integrated into the school setting. Twenty students ranging in age from 7 to 17 were recruited for this study. Data was used from 14 subjects, 12 males (2 Hispanic, 1 African American, and 10 Caucasian) and 2 females (1 Hispanic, 1 Caucasian.) The subject pool was reduced due to non-compliance or the students. moving from the school district. Significant effect size was obtained in the treatment group in areas pertaining to visual perception and motor coordination. However, significant effect sizes in other areas were obtained when the control group scores worsened. The inclusion of student subjects who, perhaps, did not meet stringent criterion of attention deficit may have skewed the results. The small number of students in the study may have hindered accurate measures of statistical significance. Conversely, the information obtained from this study may offer insight to school districts in providing their students an alternate/adjunct to psychopharmacological medication and a non- invasive method of helping students with psycho-social challenges.
Contributing Partner: UNT Libraries
Electroencephalographic Events During the Wisconsin Card Sorting Test

Electroencephalographic Events During the Wisconsin Card Sorting Test

Date: August 1998
Creator: DeBeus, Mary
Description: Quantitative electroencephalography (QEEG) was used in this study to describe cognitive processing, particularly brain locations used, during performance of the Wisconsin Card Sorting Test (WCST). The hypothesis was that significant cognitive functioning is not limited to the frontal lobes. Significant EEG activity was found in non-frontal areas as well as frontal areas.
Contributing Partner: UNT Libraries
Electrolysis of Aluminum Solutions in a Magnetic Field

Electrolysis of Aluminum Solutions in a Magnetic Field

Date: May 1950
Creator: Wood, Charles E.
Description: None
Contributing Partner: UNT Libraries
Electromagnetic aftereffects of near-death experiences.

Electromagnetic aftereffects of near-death experiences.

Date: August 2008
Creator: Nouri, Farnoosh Massoudian
Description: The purpose of this quantitative study was first to investigate the comparative incidence of electromagnetic aftereffects (EMEs) during the past year among near-death experiencers (NDErs), people who experienced a close brush with death without an NDE (CBrs), and people who reported never having experienced a close brush with death (LCErs). The second purpose was to investigate a possible change in EME incidence among the three groups before and after a critical life event. The third purpose was to investigate the relationship between the reported overall depth and specific components of the subjective experiences of people who have had a close brush with death -- NDErs and CBrs -- and their reported incidence of EMEs. I used the Near-Death Experience Scale (Greyson, 1983), and developed the Close Brush with Death Question form, Life Changing Event Question form, and Electromagnetic Effects Questionnaire for this study. The final sample included 36 NDErs, 20 CBrs, and 46 LCErs. The results of this study firmly supported more reported problems with EM devices experienced by NDErs compared to CBrs or LCErs. Especially with respect to EM devices such as lights and cell phones, as well as the emotional state of individuals affecting EM devices, this study ...
Contributing Partner: UNT Libraries
Electromagnetic Shielding Properties of Iron Oxide Impregnated Kenaf Bast Fiberboard

Electromagnetic Shielding Properties of Iron Oxide Impregnated Kenaf Bast Fiberboard

Date: December 2014
Creator: Ding, Zhiguang
Description: The electromagnetic shielding effectiveness of kenaf bast fiber based composites with different iron oxide impregnation levels was investigated. The kenaf fibers were retted to remove the lignin and extractives from the pores in fibers, and then magnetized. Using the unsaturated polyester and the magnetized fibers, kenaf fiber based composites were manufactured by compression molding process. The transmission energies of the composites were characterized when the composite samples were exposed under the irradiation of electromagnetic (EM) wave with a changing frequency from 9 GHz to 11 GHz. Using the scanning electron microscope (SEM), the iron oxide nanoparticles were observed on the surfaces and inside the micropore structures of single fibers. The SEM images revealed that the composite’s EM shielding effectiveness was increased due to the adhesion of the iron oxide crystals to the kenaf fiber surfaces. As the Fe content increased from 0% to 6.8%, 15.9% and 18.0%, the total surface free energy of kenaf fibers with magnetizing treat increased from 44.77 mJ/m2 to 46.07 mJ/m2, 48.78 mJ/m2 and 53.02 mJ/m2, respectively, while the modulus of elasticity (MOE) reduced from 2,875 MPa to 2,729 MPa, 2,487 MPa and 2,007 MPa, respectively. Meanwhile, the shielding effectiveness was increased from 30-50% to 60-70%, ...
Contributing Partner: UNT Libraries