Stimulus salience and retrospective revaluation.

The effect of conditioning or extinguishing the more salient element of a previously reinforced compound on responding to the less salient element of that compound was assessed in rats. Experiment 1 established that the 2 elements making up an audiovisual compound differed significantly in salience. In Experiment 2A, compound conditioning was followed by either reinforcement or extinction of either the less or more salient element. On test, evidence of retrospective revaluation of the less salient element was found but not of the more salient element. In Experiment 2B, extinction of the more salient element was found to be more effective than its reinforcement in producing retrospective revaluation of the less salient element. The implications of these results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reactive sputtering of SiO2-TiO2 thin film from composite Six/TiO2 targets

Coatings of SiO₂-TiO₂ films are frequently used in a number of optical thin film applications. In this work we present results from depositing films with variable Si/Ti ratios prepared by reactive sputtering. The different Si/Ti ratios were obtained by varying the target composition of composite single targets. Compared to co-sputtering this facilitates process control and composition uniformity of the films. Varying the oxygen supply during sputter deposition can result in films ranging from metallic/substoichiometric to stoichiometric oxides. Transmittance spectra of the different films are presented and the optical constants are determined from these spectra. Furthermore, the deposition process, films structure and composition of the films are discussed. The study shows that by choosing the right composition and working in the proper oxygen flow range, it is possible to tune the refractive index.     

Influence of the target composition on reactively sputtered titanium oxide films

Titanium dioxide thin films have many interesting properties and are used in various applications. High refractive index of titania makes it attractive for the glass coating industry, where it is used in low-emissivity and antireflective coatings. Magnetron sputtering is the most common deposition technique for large area coatings and a high deposition rate is therefore of obvious interest. It has been shown previously that high rate can be achieved using substoichiometric targets. This work deals with reactive magnetron sputtering of titanium oxide films from TiO_x targets with different oxygen contents.The deposition rate and hysteresis behaviour are disclosed. Films were prepared at various oxygen flows and all films were deposited onto glass and silicon substrates with no external heating. The elemental compositions and structures of deposited films were evaluated by means of X-ray photoelectron spectroscopy, elastic recoil detection analysis and X-ray diffraction. All deposited films were X-ray amorphous. No significant effect of the target composition on the optical properties of coatings was observed. However, the residual atmosphere is shown to contribute to the oxidation of growing films.     

The influence of virtual sample size on confidence and causal-strength judgments.

The authors investigated whether confidence in causal judgments varies with virtual sample size--the frequency of cases in which the outcome is (a) absent before the introduction of a generative cause or (b) present before the introduction of a preventive cause. Participants were asked to evaluate the influence of various candidate causes on an outcome as well as to rate their confidence in those judgments. They were presented with information on the relative frequencies of the outcome given the presence and absence of various candidate causes. These relative frequencies, sample size, and the direction of the causal influence (generative vs. preventive) were manipulated. It was found that both virtual and actual sample size affected confidence. Further, confidence affected estimates of strength, but confidence and strength are dissociable. The results enable a consistent explanation of the puzzling previous finding that observed causal-strength ratings often deviated from the predictions of both of the 2 dominant models of causal strength. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extracting functional equivalence from reversing contingencies.

In 2 experiments assessing acquired equivalence, human participants were initially presented with 4 cues, 2 of which were paired with 1 outcome and 2 of which were paired with a 2nd outcome. These contingencies were then reversed across several training blocks such that, although each cue was paired equally often with each of the two outcomes across blocks, cues A and B always signaled the same outcome within blocks (as did cues C and D). In both experiments, performance on a subsequent transfer discrimination was enhanced when participants were required to generalize between stimuli that had been paired with the same outcome within each block of training. Additional tests did not yield evidence of a bias toward a specific set of cue–outcome contingencies in either experiment. Moreover, interviews conducted at the end of Experiment 2 revealed that performance on the transfer discrimination was enhanced only in participants who discovered the equivalence relationships during initial training. The results challenge simple associative, and attentional, accounts of acquired equivalence and favor the view that this effect is mediated by comparisons of the similarity of adjacent cue–outcome structures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrical characterization of wurtzite (Al,B)N thin films

Wurtzite aluminum nitride (w-AlN) thin films are of great interest for electro-acoustic applications and their material properties have in recent years been extensively studied. One way to tailor material properties is to vary the composition by adding other elements. Boron is an element that can take the place of aluminum in the crystal lattice of w-AlN. In the present study, polycrystalline w-(Al,B)N thin films were grown on p-Si(100) and Al/p-Si(100) substrates by pulsed DC reactive magnetron sputtering from a single Al/B target. MIS and MIM structures were fabricated to investigate the electrical properties of w-(Al,B)N thin films. Important dielectric thin film properties for microelectronics applications are the breakdown field, the permittivity (κ) and leakage current through the film. The (Al,B)N thin film is found to have a dielectric strength of ～3 × 10⁶ V cm^?1 and a κ close to 12. The measured leakage current through the film is assumed to be mainly due to Frenkel–Poole emission with a trap energy at 0.71 eV below the conduction band edge.