Electrochemical Synthesis and Characterization of Inorganic Materials from Aqueous Solutions

Access: Use of this item is restricted to the UNT Community
The dissertation consists of the following three sections: 1. Hydroxyapatite (HA) coatings. In this work, we deposited HA precursor films from weak basic electrolytic solution (pH= 8-9) via an electrochemical approach; the deposits were changed into crystallite coatings of hydroxyapatite by sintering at specific temperatures (600-800 ºC). The formed coatings were mainly characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). XRD patterns show well-defined peaks of HA when sintered under vacuum conditions. FTIR measurements indicate the existence of hydroxyl groups, which were confirmed by the characteristic intensity of the stretching and bending bands at ~3575 and ~630 cm-1, respectively. The SEM shows an adhesive, crack free morphology for the double-layer coating surface of the samples sintered in a vacuum furnace. 2. Silver/polymer/clay nanocomposites. Silver nanoparticles were prepared in layered clay mineral (montmorillonite)/polymer (PVP: poly (vinyl pyrrolidone)) suspension by an electrochemical approach. The silver particles formed in the bulk suspension were stabilized by the PVP and partially exfoliated clay platelets, which acted as protective colloids to prevent coagulation of silver nanoparticles together. The synthesized silver nanoparticles/montmorillonite/PVP composite was characterized and identified by XRD, SEM, and TEM (transmission electron microscopy) measurements. 3. Ce-doped lead …
Date: December 2006
Creator: Yuan, Qiuhua
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Influence of executive function on medication adherence in neurologically impaired and non-impaired elderly.

Access: Use of this item is restricted to the UNT Community
Medication non-compliance has become one of the most prevalent reasons for hospitalization and doctor's visits by the elderly. As the elderly population is more likely to have decreased cognitive abilities, it is suggested that neuropsychological factors, especially executive function, are more influential in medication non-compliance than once thought. This study looked at executive function performance on a traditional battery of neuropsychological tests, self-report of perceived ability to perform executive function tasks, and the newly developed Pillbox Test, a performance based IADL measure. The Pillbox Test is designed to replicate a type of medication-management specific IADL as a means to asses executive function. Standard executive function measures only tap a portion of executive function, but it is believed that the Pillbox Test incorporates all four theoretical domains of executive function. The multiple measures of executive function performance were compared in three prevalent subgroups of the elderly population (mixed neurological group, cardiac medical-control group, and healthy community-control group). Results found significant differences, where the community-control and cardiac groups outperformed the mixed neurological group on the large majority of executive function tasks. Smaller differences were also noted between the community-control and cardiac groups and between the cardiac and mixed neurological groups. Together, these …
Date: August 2006
Creator: Zartman, Andrea Leigh
Object Type: Thesis or Dissertation
System: The UNT Digital Library

A social capital perspective on IT professionals' work behavior and attitude.

Access: Use of this item is restricted to the UNT Community
Abstract Attracting and developing information technology (IT) professionals is one of the top concerns for companies. Although much research has been conducted about the job behavior and attitudes of IT professionals over the last three decades, findings are inconclusive and contradictory. This suggests that something may be missing in how we examine this phenomenon. Most of this research is drawn from theories of motivation, very little examines the effect of social relationships on IT professionals' behavior and attitude. Yet, social capital theory suggests that job behavior and attitude may be greatly influenced by these relationships. This suggests that IT professionals' social capital warrants empirical examination. The primary research question that this dissertation addresses is how social capital affects IT professionals' work attitude and behavior including job satisfaction, organizational citizenship behavior, job performance and turnover intention. The research model in this dissertation examines the influence of three aspects of social capital on IT professionals' job attitude and work behavior: tie strength, the number of ties and the structural holes. Data were collected from 129 IT professionals from a range of jobs, organizations and industries. Results indicate that tie strength in the organization of an IT professional is positively related to job …
Date: August 2006
Creator: Zhang, Lixuan
Object Type: Thesis or Dissertation
System: The UNT Digital Library