INTRODUCTION Incorporating a feldspar chemical bond between alumina filler particles is expected to increase the wear-resistant and flexural strength properties. AIMS AND OBJECTIVES An investigation was carried out to evaluate the influence of the feldspar chemical bonding between alumina filler particles on wear and flexural strength of experimental alumina/feldspar dental composites. It was...

The thermodynamics of self-assembling systems are discussed in terms of the chemical interactions and the intermolecular forces between species. It is clear that there are both theoretical and practical limitations on the dimensions and the structural regularity of these systems. These considerations are made with reference to the microphase separation that occurs in block copolymer (BCP) syste...

OBJECTIVE Recent studies have shown that adhesives containing acidic monomers combined with composites can adversely effect the polymerization reaction producing low bond strengths. This phenomenon may also occur in making composite build-ups, jeopardizing one of the key factors for a successful core build-up restoration. The aim of this study was to investigate the contraction stress developme...

The thermal decomposition behavior of olive hydroxytyrosol (HT) was first studied using thermogravimetry (TG). Cracked chemical bond and evolved gas analysis during the thermal decomposition process of HT were also investigated using thermogravimetry coupled with infrared spectroscopy (TG-FTIR). Thermogravimetry-Differential thermogravimetry (TG-DTG) curves revealed that the thermal decompositi...

Recent advances in dynamic force microscopy show that it is possible to measure the forces between atomically sharp tips and particular atomic positions on surfaces as a function of distance. However, on most ionic surfaces, the positive and negative ions can so far not be distinguished. In this paper, we use the CaF2(111) surface, where atomic resolution force microscopy has allowed identifica...

The relaxation of helical structures very close to equilibrium is observed via transient 2D IR spectroscopy. An initial distribution of synthetically distorted helices having an unnatural bridge linking the 10th and 12th residues of an alanine-rich α-helix is released to evolve into the equilibrium distribution of α-helix conformations. The bridge constrains the structure to be slightly displac...

Conspectus There is need in the molecular simulation community to develop new quantum mechanical (QM) methods that can be routinely applied to the simulation of large molecular systems in complex, heterogeneous condensed phase environments. Although conventional methods, such as the hybrid quantum mechanical/molecular mechanical (QM/MM) method, are adequate for many problems, there remain other...

Dielectric properties, including linear (refractive index) and second-order nonlinear optical responses, of LiNb12yTayO3-type mixed single crystals with y ˆ 0:00; 0.81, 0.92, 0.97, and 1.00 have been quantitatively studied. Based on the corresponding crystal compositions, the chemical bond method was applied. The results show that the dielectric susceptibilities at 1.064 mm decrease remarkably ...

Nonlinearity in macroscopic mechanical systems may lead to abundant phenomena for fundamental studies and potential applications. However, it is difficult to generate nonlinearity due to the fact that macroscopic mechanical systems follow Hooke's law and respond linearly to external force, unless strong drive is used. Here we propose and experimentally realize high cubic nonlinear response in a...

The influence of cation-π interactions on the strength and nature of intramolecular O...H hydrogen bond has been investigated by quantum chemical calculations in orthohydroxy benzaldehyde (HBA) compound. Ab initio calculations have been performed at MP2/6-311++G** level of theory. Vibrational frequencies and physical properties such as chemical potential and chemical hardness of these compounds...