Comparative analysis of different preparation methods of chalcogenide glasses: Molecular dynamics structure simulations

Two different preparation methods (liquid-quenching and evaporation) of chalcogenide glasses have been investigated by molecular dynamics simulations. Our particular aim was to determine how the structural changes occur due to the different preparation methods. We applied a classical empirical three-body potential of selenium to describe the interactions between atoms. Our simulation shows that a significant difference can be observed in the homogeneities

A Study on the Relationship of Consumers’ Mental Image and Perceived Values of Brand Products

Today’s competitive world has transformed the role of consumers in organizations, as consumers are present in all processes, from production phases to the delivery of products. Thus, the universities researchers’ and traders’ attention have shifted towards the consumers’ mental image of the brands to the extent that they have included allocated sections in their mission statements and company objectives to the consumers’ mental image. The present article attempts to study the effect of the Shampoo Brand’s mental image on the perceptual values of the consumers. In this perspective, the present research is applied and is descriptive. The purchase process and preserving the health of hair, scalp and reducing hair loss and the most important of all, maintaining the beauty of appearance is of outmost importance for women; choosing the right shampoo is always their crucial concerns specifically in Islamic societies like Iran where the hair is covered throughout the day and the absence of breathing scalp gets highlighted. Thus, participants include the Alzahra female students shampoo consumers who has responded to the questionnaire as the main research tool. The analysis using SPSS and LISREL proved research hypothesis. That is, the mental image of brand is positively related to perceived quality and price/cost of the products. Considering that perceived quality and price the elements of perceived value, results confirm such relationship in Alzahra University as the only Iranian women university

International Scientometric Systems: A Study of Acceptance Management in Academic Communities

The reluctance of university members to enter their information in International Scientometric Systems (ISSs) is counterproductive behavior for human resource management for international university rankings. The explicit goal of this research was to identify the necessary conditions for ISSs acceptance management in an Iranian academic community. To identify factors affecting the acceptance of ISSs and explore members’ attitudes towards them after a focused literature review, user feedback in training classes of ISSs was recorded through the researcher's participation during two semesters. This information was placed as components of a self-made questionnaire after multiple codings based on grand theory.  Then, a self-made questionnaire technique was used to investigate correlations between these factors. Snowball sampling collected data from 86 expert users of this system, and the hypotheses were tested.  In entering information in ISSs, experience of using ISSs, facilitating conditions, expected effort, and expected performance were identified. Finally, the relationships of these variables were presented based on the path analysis model. The results showed that usefulness, expected effort, experience, and facilitating conditions effectively use the systems through the willingness to use ISSs. However, the members were unwilling to use ISSs because they were not well justified about the micro and macro goals of the university ranking systems. Completing information in these diverse systems is considered time-consuming and repetitive. The existing rules for each system are considered cumbersome. Access to these systems' cookies to their personal information is not considered safe and desirable. The results' significance, implications, and limitations have also been deliberated for further research

Experimental and ab initio molecular dynamics study of the structure and physical properties of liquid GeTe

GeTe is a prototypical phase-change material employed in data storage devices. In this work, the atomic structure of liquid GeTe is studied by x-ray and neutron diffraction in the temperature range from 1197 to 998 K. The dynamic viscosity is measured from 1273 to 953 K, which is 55 K below the solidification point, using an oscillating-cup viscometer. The density of liquid GeTe between 1293 and 973 K is determined by the high-energy γ-ray attenuation method. The experiments are complemented with ab initio molecular dynamics (AIMD) simulations based on density functional theory (DFT). Compatibility of the AIMD-DFT models with the diffraction data is proven by simultaneous fitting of all data sets in the frame of the reverse Monte Carlo simulation technique. It is shown that octahedral order dominates in liquid GeTe, although tetrahedral structures are also present. The viscosity of the equilibrium and weakly undercooled liquid GeTe obeys the Arrhenius law with a small activation energy of the order of 0.3 eV, which is indicative of a highly fragile liquid. The calculated density of states and electronic wave functions point to the existence of a pseudogap and localized electron states within the gap in the equilibrium liquid near the melting point as well as in the undercooled liquid

Effect of Topic Familiarity on Summary Writing of Iranian Intermediate EFL Learners

One of the most typical and crucial academic writing skills for L2 learners is summary writing. It is a complex activity that requires students’ deep engagement with a text through reading, understanding, paraphrasing and reorganizing and finally constructing a summary in their own words. This study intends to investigate the effect of topic familiarity on Iranian foreign language learners’ summary writing. Its aim is to find out whether there was any significant effect on learners’ summary writing performance with regard to topic familiarity. The participants of the study were 40 female intermediate Iranian EFL learners, who were given instructions for different processes used in summary writing. After each session of instruction, four passages with two different topics familiar and unfamiliar were given to learners in order to be summarized. Two passages had familiar topics; they were related to Iranian culture, so the learners had sufficient background knowledge about them. The two other unfamiliar passages were related to foreign culture, with no preexisting knowledge on the part of the learners. Finally, according to the statistics analysis, it was revealed that learners’ summary writings were significantly affected by topic familiarity. Familiar topics by the activation of learners’ schemata facilitated their understanding and helped them to outperform in summarizing familiar topics than unfamiliar ones. In other words, learners’ familiarity with Iranian culture and their prior knowledge of the content facilitated learners’ reading comprehension as well as their summary writing performance. The result can provide second language teachers with appropriate criteria so that they can improve learners’ writing skills by providing various writing strategies according to learners’ needs and being flexible in selecting teaching techniques, as adhering rigidly to a specific approach will not solve all the forthcoming problems of the learners

Structure, electronic, and vibrational properties of glassy Ga11Ge11Te78: Experimentally constrained density functional study

The atomic structure and electronic and vibrational properties of glassy Ga11Ge11Te78 have been studied by combining density functional (DF) simulations with x-ray (XRD) and neutron diffraction (ND), extended x-ray absorption fine structure (EXAFS), and Raman spectroscopies. The final DF structure (540 atoms) was refined using reverse Monte Carlo methods to reproduce the XRD and ND data as well as Ge and Ga K-edge EXAFS spectra, while maintaining a semiconducting band gap and a total energy close to the DF minimum. The local coordination of Ga is tetrahedral, while Ge has twice as many tetrahedral as defective octahedral configurations. The average coordination numbers are Ga, 4.1, Ge, 3.8, and Te, 2.6. The chemical bonding around Ga involves Ga 4s, Ga 4p, Te 5s, and Te 5p orbitals, and the bond strengths show bonding close to covalent, as in Ge. There are fewer Te chains and cavities than in amorphous Te, and a prepeak in the structure factor at 1.0 angstrom(-1) indicates medium-range order of the Ga/Ge network. Density functional calculations show that contributions of Te-Te, Ga-Te, and Ge-Te bonds dominate the experimental Raman spectra in the 110-150 cm(-1) range