A new type of computer-controlled instrument has been developed to measure microviscoelastic properties of thin materials. It can independently control and measure indentation loads and depths in situ revealing information about material creep and relaxation. Sample and indenter positions are measured with a specially designed polarization interferometer. Indenter loadings can be varied between 0.5 and 10 grams and held constant to ±41 mg. The resulting indentation depths can be measured in situ to ±1.2 nm. The load required to maintain constant indentation depths from 0.1 to 5.0 microns can be measured in situ to ±3.3 mg and the depth held constant to ±15 nm.

Two different time-resolved spectroscopic techniques are discussed theoretically and demonstrated experimentally in dilute gases. The first technique involves extending the advantages of Stark-effect based time-resolved spectroscopy to non-polar molecules. This involves the development of a stable, TEM₀₀ mode, cw, CO₂ laser capable of switching rapidly and controllably between two frequencies. Design problems and output characteristics are discussed. The frequency switchable laser is applied to the CO₂ 10.6 μm P(16) coincidence with the non-polar molecule SF₆. The population relaxation time, T₁, is measured using two-pulse delayed nutation. The decay of induced dipoles is studied using the phenomenon of photon echoes. It is found that the echoes decay in a manner characteristic of dephasing dominated by velocity-changing collisions. A fit of the data to a model for such decays gives values of γ(ab) ≡ 1/T₂ (the non-velocity-changing contribution to the dipole decay rate), Γ(VC) (the total probability of a velocity-changing collision per unit time), and Δu which is related to the mean velocity change of SF₆ upon a velocity changing collision. A comparison with the published results of the similar Stark experiments on C¹³ H₃F are made. The second technique involves the development of an alternative to the pulsed excitation typically used in time-resolved T₁ studies. This involves inversion of a portion of the velocity distribution by adiabatic rapid passage (ARP) techniques. The center of this portion is then probed in the manner of previous delayed nutation experiments. The system preparation is shown theoretically to be different and simpler than the pulse case. In addition, ARP preparation gives a larger signal than two-pulse delayed nutation experiments. ARP experiments on N¹⁴H₃ and N¹⁵H₃ are described and compared to two-pulse delayed notation experiments. The single exponential decay best fits to the data from the two methods are found to be in agreement. We would expect the N¹⁵H₃ results to be very similar to the N¹⁴H₃ results, though reduced rotational resonance effects in its upper state should give it an overall slower decay. It is indeed found that the decay appears to be a simple exponential as did the N¹⁴H₃ data over the time range studied. The pressure dependent single exponential decay rate for N¹⁵H₃ is however roughly 45% larger than the rate for N¹⁴H₃ in the pressure range from 0.5 to 9 mTorr.

GeₓSe₍₁₋ₓ₎ and AsₓSe₍₁₋ₓ₎ glasses have found use in many technological applications due to their excellent rheological properties and their wide IR transparency window. However, the low glass transition temperatures of these glasses leads to large changes in their properties, due to structural relaxation, over the weeks and months subsequent to their fabrication. Thus, obtaining a more thorough understanding of structural relaxation and its relation to the structure, composition, and processing of these glasses is important in furthering their use. Structural investigations, using NMR and Raman spectroscopies, performed on the GeₓSe₍₁₋ₓ₎ family of glasses show that the structure of these glasses is composed of two distinct microdomains. One corresponds to a rigid GeSe₂-like domain and the other corresponds to a floppy Se domain. These results are compared to other existing structural models for GeₓSe₍₁₋ₓ₎ glasses. Enthalpy measurements on both GeSe₉ and GeSe₄ optical fibers which were aged up to five years demonstrate that both compositions undergo a large amount of enthalpy relaxation in this time period. Raman spectroscopy performed concurrently with enthalpy measurements on the same GeSe₉ and GeSe₄ fibers shows that one of the structural changes taking place within the glass network is the conversion of edgesharing to corner-sharing tetrahedra in the GeSe₂-like phase. Moreover, the rate at which this conversion takes place is shown to be similar to the rate of enthalpy relaxation, suggesting that this structural change is one of the main mechanisms for structural relaxation in GeₓSe₍₁₋ₓ₎ glasses. Implementation of the Tool-Narayanaswamy-Moynihan (TNM) model as a hybrid computer model allowing the prediction of the four relaxation parameters Δh*, log(A), x, and β via optimization of simulated and experimental data was accomplished. It was found that a multi-rate version of the TNM model, which obtains an average set of model parameters via optimization of multiple experimental thermal histories simultaneously, was able to predict relaxation parameters for AsₓSe₍₁₋ₓ₎ glasses within the 2.10 ≤ <r> ≤ 2.50 compositional domain, where <r> is the average bond coordination of the glass network as defined by the Phillips and Thorpe constraints model. Above <r> = 2.50, however, the model fails, due to a bimodal distribution of relaxation times within the glass structure contrary to the TNM model assumption of a unimodal distribution of relaxation times, thus rendering the model inapplicable. Muti-rate modeling of the GeₓSe₍₁₋ₓ₎ family of glasses was also attempted, however the TNM model also fails for this family of glasses due to the inherently bimodal distribution of relaxation times which arises from their bimodal structure.

No description available.

This study was designed to investigate the effects of Relaxation, Positive Suggestion and Success Imagery (RSI) on locus of control and scores on teacher-made exams in an undergraduate college population. As well as to investigate interactions between locus of control and the exam scores. The sample, composed of 52 females and 2 males ranging in age from 18-47, confirmed previous findings that women in college do not show an interaction between locus of control and grades. Furthermore, RSI did not appear to significantly change locus of control or exam scores for the whole sample. However, the data suggests RSI to effectively change locus of control and grades with the younger aged students, inferring that an internal locus of control is easier to develop and grades are easier to influence in younger students with this procedure.

No description available.

The de Broglie-Bohm causal interpretation of quantum mechanics is discussed, and applied to the hydrogen atom in several contexts. Prominent critiques of the causal program are noted and responses are given; it is argued that the de Broglie-Bohm theory is of notable interest to physics. Using the causal theory, electron trajectories are found for the conventional Schr??dinger, Pauli and Dirac hydrogen eigenstates. In the Schr??dinger case, an additional term is used to account for the spin; this term was not present in the original formulation of the theory but is necessary for the theory to be embedded in a relativistic formulation. In the Schr??dinger, Pauli and Dirac cases, the eigenstate trajectories are shown to be circular, with electron motion revolving around the <i>z</i>-axis. Electron trajectories are also found for the 1<i>s</i>-2<i>p</i>0 transition problem under the Schr??dinger equation; it is shown that the transition can be characterized by a comparison of the trajectory to the relevant eigenstate trajectories. The structures of the computed trajectories are relevant to the question of the possible evolution of a quantum distribution towards the standard quantum distribution (quantum equilibrium); this process is known as quantum relaxation. The transition problem is generalized to include all possible transitions in hydrogen stimulated by semi-classical radiation, and all of the trajectories found are examined in light of their implications for the evolution of the distribution to the standard distribution. Several promising avenues for future research are discussed.

This study investigated the value of headache presence during elecromyographic (EMG) feedback relaxation training and the contribution made by home relaxation practice in the elimination of tension headache. Eighteen participants, mainly coeds in their twenties, recorded headache and medication data for two baseline weeks, and were assigned to one of three training groups. Group A received EMG feedback training with headache presence during the session and home relaxation practice. Group B received EMG feedback without headache Presence and home practice. Group C received only home relaxation practice. Statistically significant treatment differences were not found, but declining trends of headache activity and medication use tend to support the efficacy of EMG training with headache presence.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.