On the possibility of tuning the energy separation between space-quantized levels in a quantum well

The idea about change of energy distances between space-quantized energy levels by ionization of an impurity delta layer situated within a quantum well (QW) is put forward and justified. The self-consistent solutions of Schrödinger, Poisson, and electroneutrality equations made for n-type SiGe/Si/SiGe rectangular QW show that the effect really exists and the most dramatic changes can be observed for an edge-delta-doped QW structure.     

Effect of couple stress at the interfaces of a nano-hole on the anti-plane electro-mechanical behavior

In piezoelectric nanocomposites, surface/interface plays an important role in determining the size-dependent behavior of media. Within the framework of couple stress, the effect of surface/interface around a nano-hole on the anti-plane electro-mechanical behavior is examined. By introducing a surface/interface model, the stress and electric displacement effects on the size-dependent behavior are both considered. The governing equations in piezoelectric materials are decoupled into the classical ones. The displacement and electric potential are expressed by Bessel functions. By satisfying the boundary conditions around the hole with the interface/surface effect, the expanded coefficients are obtained. Through analysis, it is shown that the mechanical and electrical fields drastically depend on the relative size of the hole with respect to the characteristic length of the material. The effects of couple stresses on the stress and electric field are also addressed. Comparison with the existing results is also given.     

Effect of a nanoporous surface on photoluminescence from nanopatterned GaN thin films fabricated by anodic alumina templates

GaN photonic crystal slabs on InGaN/GaN multi-quantum well light-emitting diodes have been formed by dry etching using nanoporous anodic alumina templates, which have a periodic lattice constant of 105 nm and a hole diameter of 45 nm. The photonic crystal slab shows an enhanced intensity of photoluminescence due to the nanohole pattern array producing Fabry–Perot like interference. A rough surface of nanoholes results in a broad spectrum with a small oscillation, and well-ordered multiple facets of nanoholes results in a relatively sharp spectrum with a large oscillation.     

Dielectric and spectrometric investigations of binary mixtures of tetrahydrofuran with propionic acid

The static permittivity (ε_m ) and the permittivity at the high-frequency limit (ε_∞m ) of a binary mixture of propionic acid with tetrahydrofuran (THF) have been determined for different concentrations at temperatures of 303, 308, 313, and 318 K. The data have been used to compute the Kirkwood correlation factor, the excess permittivity, and the excess free-energy of the mixtures. The Kirkwood correlation factor is found to increase with increasing THF concentration. The mixture exhibited positive values of the excess permittivity and negative values of the excess free-energy of mixing, respectively. UV-Vis and FT-IR spectral measurements have also been carried out. The observed bathochromism and hypochromism in the UV-Vis spectra have been explained in terms of complex formation and ordering of dipoles of the complex. The FT-IR spectrum of the mixture shows considerable shifts in the positions of some of the absorption bands, indicating extensive hydrogen bonding between solute and solvent molecules.     

The energetics and interactions of random dislocation walls

Abstract

Regular dislocation walls, where dislocations are spaced equally along the wall direction, are a popular idealization for modelling the arrangement and interactions of excess dislocations in plastic deformation. The assumption of regular walls is motivated by the fact that such walls represent minimum energy arrangements for dislocations of the same sign, and it allows to use the analytically known short-ranged stress fields of such walls for analyzing the structure of plastic boundary layers. In order to critically evaluate the physical robustness of models based on regular walls, we investigate their random counterparts and demonstrate that the energetics and interactions of such non-periodic dislocation arrangements differ completely from the periodic wall arrangements. Implications of our results for the modelling of plastic boundary layers and dislocation-grain boundary interactions are discussed.     

Islam,HIV/AIDS and activism: a critical analysis of some themes in Positive Muslims' ‘theology of compassion’

The present article is a critical analysis of the South African organization Positive Muslims' ‘theology of compassion’, put forward by its proponents as a Muslim religious initiative to combat the spread of HIV/AIDS and the stigmatization of those affected by the disease. The article addresses the hermeneutics applied and the results reached in relation to a wider contemporary Muslim religious discourse on HIV/AIDS. It also connects the ‘theology of compassion’ to a broader transnational movement of progressive Islam, of which the ‘theology of compassion’ is a practical, grass-roots application. The main analytical focus, however, is on the way in which certain features in this theology are shaped by basic assumptions on the part of its producers concerning the beliefs, emotions and background knowledge of its main stated consumers: believing Muslims.     

Slow and steady wins the race: Life history,mate value,and mate settling

Life history theory explains how individuals decide to invest their limited resources, which involves several trade-offs. Particularly relevant to the current work, individuals can choose to invest in current or delayed reproduction (a slow life history strategy), which implicates a trade-off between the quantity and the quality of one’s offspring. Choosing to delay reproduction allows for increased self-investment, and previous research has demonstrated that traits requiring self-investment are related to higher mate value. As such, the current study hypothesizes that slow life history strategy will predict high personal mate value and high levels of partner mate-value within heterosexual partnerships. Similarly, those with a slow life history strategy should display fewer tendencies toward mate-settling. The current work employs both subjective and objective measures of mate value within mateships to investigate these hypothesized relationships. As hypothesized, significant positive relationships among life history and mate value were detected, suggesting that a slower life history strategy corresponds to high ratings of mate value for both self and partner. Also, life history strategy is a significant predictor of subjective, objective, and Mate Value Inventory ratings of partner and self. Further implications and potential future works are discussed.     

Positive perception: A three dimensional model and a scale

Traits and perceptions that predict psychological and physical well-being have been the focus of great interest in Positive Psychology. The paper focused on positive perception (PP) as a case in point. A three dimensional model of PP is proposed. PP represents a general tendency to evaluate positively one’s abilities, one’s past, and human nature. The construction of an 8-item self-report measure of PP, the Positive Perception Scale (PPS), is detailed. Three samples of university students and a national sample of working couples (total N = 796) helped demonstrate various psychometric aspects of the PPS. The studies confirmed the three dimensional model of PP, demonstrated it as both a trait and a state and the PPS as a valid and reliable scale, for both researchers and practitioners.     

Preference for online social interactions among young people: Direct and indirect effects of emotional intelligence

The social skills model of generalized problematic internet use predicts that individuals who perceive themselves as having low social competencies are at risk to develop a preference for online social interactions (POSI), which, in turn, might lead to compulsive use of Internet communication services. The present study aims to investigate if self-reported emotional intelligence (EI)—interpersonal and intrapersonal abilities—has an effect on POSI levels, and if this effect is mediated by the subjective importance attached to the major controllability (RC) and reduced non-verbal cues (RNVC) of computer mediated communication. 192 high schools and college students were recruited. Results from structural equation modeling show that Intrapersonal EI predicts both RC and RNVC, which, in turn, predicts the level of POSI. A partial mediation effect was found. On the other hand, Interpersonal EI is significantly associated with POSI, but this association cannot be explained by RC and RNVC. Its effect on POSI seems to be either direct or explained by variables not considered in the present study.