Search

We have described a method for structural parameters optimization of GaN/AlGaN multiple quantum well based up-converter for silicon solar cells. It involves a systematic tuning of individual step quantum wells by use of the genetic algorithm for global optimization. In quantum well structures, the up-conversion process can be achieved by utilizing nonlinear optical effects based on intersubband transitions. Both single and double step quantum wells have been tested in order to maximize the second order susceptibility derived from the density matrix formalism. The results obtained for single step wells proved slightly better and have been further pursued to obtain a more complex design, optimized for conversion of an entire range of incident photon energies. [ABSTRACT FROM AUTHOR]

A computational model for the optimization of the second order optical nonlinearities in GaInAs/AlInAs quantum cascade laser structures is presented. The set of structure parameters that lead to improved device performance was obtained through the implementation of the Genetic Algorithm. In the following step, the linear and second harmonic generation power were calculated by self-consistently solving the system of rate equations for carriers and photons. This rate equation system included both stimulated and simultaneous double photon absorption processes that occur between the levels relevant for second harmonic generation, and material-dependent effective mass, as well as band nonparabolicity, were taken into account. The developed method is general, in the sense that it can be applied to any higher order effect, which requires the photon density equation to be included. Specifically, we have addressed the optimization of the active region of a double quantum well In0.53Ga0.47As/Al0.48In0.52As structure and presented its output characteristics. [ABSTRACT FROM AUTHOR]

Examining the impact of green orientation and other similar practices in an organization on employees' organizational identification is becoming increasingly important. At the same time, internal green marketing is increasingly attracting the attention of researchers. However, there is a lack of studies in which the primary goal was to examine the relationship between internal green marketing, employee satisfaction in its context, and employees' organizational identification. Hence, the aim of this paper was to determine whether there is a relationship between all dimensions of internal green marketing and organizational identification of employees, as well as between employees' satisfaction and organizational identification. The online survey was conducted among employees of different organizations in the Republic of Serbia. The regression and correlation analysis was used to test the hypotheses. The obtained results showed a statistically significant positive relationship between each dimension of internal green marketing and employees' organizational identification as well as between employees' satisfaction and organizational identification. For future research, a longitudinal study is recommended, testing the relationships between these variables on a larger sample, and testing on a sample of managers.

The paper examines a part of the iconographic program in the narthex of the representative church, endowed by the Serbian king Uroš I and dedicated to the Holy Trinity. With its layout, the program is linked to the central field of the wall above the entrance to the nave and bears the characteristics of the focal point of the corresponding whole. It includes a thematic segment with a group of representations that, based on today's knowledge of painted material, can be classified as novelties and exceptional solutions. The cycle of Ecumenical Councils, with the attached depiction of a Serbian council, and the Last Supper, as the core of the group, are viewed from an angle from which they were not illuminated before. The unusual selection of scenes and the unique composition of the thematic group become clearer when one considers the scenes' place on the line that connects three important 'points' of Sopoćani's spatial and programmatic structure on the west-east axis. The 'council wall', with the Last Supper in its 'heart' communicates topographically, visually and semantically with the representation of Pentecost, which signalled the 'identity of the holy place' on the original 'face' of the building in Sopoćani (altered by later painting), at the entrance to the narthex. Moreover, the painted wall is in an equally multiple (topographical, visual, and semantic) correlation with the themes that mark the iconographic program in the sanctuary and around the opening leading into it. Apart from the repeated representation of the Pentecost, this time with a position on the wall field above the opening of the sanctuary apse, and apart from the typological representation of the Holy Trinity, situated in the eastern half of the south choir's vault, the representations in the central part of the apse are particularly relevant for observations about the parallelism and special complementarity of the themes in the sanctuary and the narthex. This is a unity consisting of a 'liturgical' variant of the Last Supper (i.e., Communion of the Apostles) and two scenes of the Appearance of the Risen Christ to the Apostles, identified with the theme of the Sending out of the Apostles-all in the same register-as well as the composition of Officiating Church Fathers in the register below, which as their coevals also includes archbishops of the Serbian Church, positioned immediately below the rendering of the Apostolic Mission. The resulting findings of the present study is the existence of a special connection of the thematic repertoire with the dedication of the church and the reception of that connection as a kind of starting point in the process of envisaging and shaping a whole with a multi-layered meaning. As it appears, a conventional framework was consciously chosen and used as an 'undercover' for additional, daring allusions.

The composition with representations of medieval rulers is a unique structure within the fresco-ensemble of the Hilandar refectory, which was signed by the painter Georgije Mitrofanović in 1621/1622, replacing the previous, three centuries older works. It depicts Serbian King Milutin and the Byzantine Emperor Andronikos II Palaiologos in a paraphrased version of the solution found in medieval portraits within the narthex of the Catholicon of the Monastery. With some modifications, it was incorporated into a new programmatic context, together with figures of Saint Simon the Monk (most likely representing the former King Uroš I) and Saint Stefan Dečanski. The formation of the latter pair is based on iconographic patterns that combine the initial theme of the pious rulers' patronage with motifs of martyrdom and unwavering faith. The new visual ensemble, featuring figures of pious and orthodox rulers from the medieval past, is completed by the insertion of the symbol of the cross between them and by placing all the figures under the protection and blessing of Christ, the Angel of Great Counsel. Why did the creator of this pictorial program connect the bygone rulers, patrons of the monastery, with a distinctive, non-traditional representation of Christ? How does the passage of time since the medieval period affect the reception of this iconographic group? What does the medallion with the cross and Christogram signify in the given arrangement? These and similar questions, mostly overlooked in previous discussions focused on the restoration aspect of Mitrofanović's work, stem from the endeavour to understand what was achieved through the characteristics and circumstances of the era in which the refectory was repainted, particularly in the context of the challenges faced by the Orthodox community within the then Ottoman state.

We present a model for calculating the optical gain in a midinfrared GaAs/AlGaAs quantum cascade laser in a magnetic field, based on solving the set of rate equations that describe the carrier density in each level, accounting for the optical- and acoustic-phonon scattering processes. The confinement caused by the magnetic field strongly modifies the lifetimes of electrons in the excited state and results in pronounced oscillations of the optical gain as a function of the field. Numerical results are presented for the structure designed to emit at λ~11.4 μm, with the magnetic field varying in the range of 10-60 T. The effects of band nonparabolicity are also included. [ABSTRACT FROM AUTHOR]

In this paper, we have tried to present the role of internal marketing (IM) in employees' organizational identification (OI) based on the review and analysis of relevant empirical studies that were published in the period from 2009 to the present. The analysis showed that IM has a significant role in increasing employees' OI (the direct impact). The impact of IM on OI also takes place through two groups of mediators: internal marketing orientation (IMO) and the adoption of IM philosophy by managers, i.e. employees' job satisfaction and organizational commitment. Employees' experience of the programmes of IM and their perceptions of IMO affect OI, rather than management's attitude. However, IM programmes without managerial support do not provide the best levels of employees' OI. When employees are encouraged by managerial support to perceive IM, then their perceptions of IM are facilitated. In addition, the similarity between the perceptions of the organization's value by the manager and his employees leads to the harmonious growth of their identification with the organization. The transfer of OI from manager to employees encourages performance growth, and improves the perceptions of service quality by customers. OI mediates the relationship between IM and employees' outcomes. In accordance with the above, this topic is recommended to both theorists and practitioners; it is still insufficiently researched i.e. applied.

The purpose of the paper was to examine the impact of internal green marketing on managers' organizational identification and the financial performance of the organizations. The empirical research was carried out by an online survey. The model proposed in this paper was tested on a sample of 53 managers of Serbian organizations in the agribusiness sector. For empirical testing of the proposed hypotheses, partial least squares structural equation modeling was used. The findings revealed that the direct effect of internal green marketing on managers' organizational identification as well as the direct effect of managers' organizational identification on financial performance is positive and statistically significant. Managers' organizational identification fully mediates the relationship between internal green marketing and financial performance. This paper can contribute to better understanding of green internal marketing and its effect on organizations, especially in the agribusiness sector. The results can be useful to managers in the agribusiness sector.

The aim of this paper is to investigate the effects of the programme for professional development of chemistry teachers on their competencies for conducting formative and summative assessment in chemistry teaching. The programme participants were 30 chemistry teachers from primary and secondary schools. Data were collected using a questionnaire at the beginning and at the end of the programme implementation. The programme included four workshops with the same structure: the introduction, group work and the discussion of the results obtained through group work. The workshops focused on: i) the assessment as a support for chemistry learning; ii) the harmonization of teaching and learning activities, formative and summative assessment, feedback from formative assessment and the criteria used to evaluate students in summative assessment; iii) the evaluation of the validity of tasks used for formative and summative assessment according to the curricula aims and the educational standards; iv) designing tasks for monitoring students’ progress towards certain educational standards. Teachers’ responses show the impact of the programme for the development of their competencies for assessment, particularly regarding formative and summative assessment and designing various kinds of assessment in accordance with the achievement standards.