ON THE ISSUE OF THE FUNCTIONAL THEORY OF ELITES: LOSSES AND POSSIBILITIES OF A NEW APPROACH

Author(s):  
Daniil O. Ryabchenko ◽  

The article examines the prerequisites for reinterpreting the concept of "elite" at the turn of the XX–XXI centuries. The author analyzes the need to change the concept of the elite as a factor of social practice, investigates the prerequisites for a retreat from the traditions of interpreting the elite in the problem field of classical sociology. The thesis about the fruitfulness of the study of the elite in the discourse of such trends of its development as sociologization, rationalization, and subjectivation is outlined. The explanatory potential of the functional and functionalist concepts of the elites is compared.

2021 ◽  
Vol 11 (15) ◽  
pp. 6862
Author(s):  
Hongzhe Wen ◽  
Xuan Luo

Perovskites have recently attracted interest in the field of solar energy due to their excellent photovoltaic properties. We herein present a new approach to the composition of lead free perovskites via mixing of halide and oxide perovskites that share the cubic ABX3 structure. Using first-principles calculations through Density Functional Theory, we systematically investigated the atomic and electronic structures of mixed perovskite compounds composed of four cubic ABX3 perovskites. Our result shows that the B and X atoms play important roles in their band structure. On the other hand, their valence bands contributed by O-2p, Rh-4p, and Ti-3p orbitals, and their electronic properties were determined by Rh-O and Ti-O bonds. With new understandings of the electronic properties of cubic halide or oxide perovskites, we lastly combined the cubic perovskites in various configurations to improve stability and tune the bandgap to values desirable for photovoltaic cell applications. Our investigations suggest that the mixed perovskite compound Cs2Sn2Cl3I3Sr2TiRhO6 produced a bandgap of 1.2 eV, which falls into the ideal range of 1.0 to 1.7 eV, indicating high photo-conversion efficiency and showing promise towards solar energy applications.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jiang Ouyang ◽  
Ling Zhang ◽  
Leijiao Li ◽  
Wei Chen ◽  
Zhongmin Tang ◽  
...  

Abstract Stanene (Sn)-based materials have been extensively applied in industrial production and daily life, but their potential biomedical application remains largely unexplored, which is due to the absence of the appropriate and effective methods for fabricating Sn-based biomaterials. Herein, we explored a new approach combining cryogenic exfoliation and liquid-phase exfoliation to successfully manufacture two-dimensional (2D) Sn nanosheets (SnNSs). The obtained SnNSs exhibited a typical sheet-like structure with an average size of ~ 100 nm and a thickness of ~ 5.1 nm. After PEGylation, the resulting PEGylated SnNSs (SnNSs@PEG) exhibited good stability, superior biocompatibility, and excellent photothermal performance, which could serve as robust photothermal agents for multi-modal imaging (fluorescence/photoacoustic/photothermal imaging)-guided photothermal elimination of cancer. Furthermore, we also used first-principles density functional theory calculations to investigate the photothermal mechanism of SnNSs, revealing that the free electrons in upper and lower layers of SnNSs contribute to the conversion of the photo to thermal. This work not only introduces a new approach to fabricate 2D SnNSs but also establishes the SnNSs-based nanomedicines for photonic cancer theranostics. This new type of SnNSs with great potential in the field of nanomedicines may spur a wave of developing Sn-based biological materials to benefit biomedical applications.


2015 ◽  
Vol 242 ◽  
pp. 434-439 ◽  
Author(s):  
Vasilii E. Gusakov

Within the framework of the density functional theory, the method was developed to calculate the band gap of semiconductors. We have evaluated the band gap for a number of monoatomic and diatomic semiconductors (Sn, Ge, Si, SiC, GaN, C, BN, AlN). The method gives the band gap of almost experimental accuracy. An important point is the fact that the developed method can be used to calculate both localized states (energy deep levels of defects in crystal), and electronic properties of nanostructures.


IUCrJ ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 497-509 ◽  
Author(s):  
Paul Benjamin Klar ◽  
Iñigo Etxebarria ◽  
Gotzon Madariaga

Synchrotron single-crystal X-ray diffraction has revealed diffuse scattering alongside sharp satellite reflections for different samples of mullite (Al4+2xSi2−2xO10−x). Structural models have been developed in (3+1)-dimensional superspace that account for vacancy ordering and Al/Si ordering based on harmonic modulation functions. A constraint scheme is presented which explains the crystal-chemical relationships between the split sites of the average structure. The modulation amplitudes of the refinements differ significantly by a factor of ∼3, which is explained in terms of different degrees of ordering,i.e.vacancies follow the same ordering principle in all samples but to different extents. A new approach is applied for the first time to determine Al/Si ordering by combining density functional theory with the modulated volumes of the tetrahedra. The presence of Si–Si diclusters indicates that the mineral classification of mullite needs to be reviewed. A description of the crystal structure of mullite must consider both the chemical composition and the degree of ordering. This is of particular importance for applications such as advanced ceramics, because the physical properties depend on the intrinsic structure of mullite.


2008 ◽  
Vol 600-603 ◽  
pp. 285-290 ◽  
Author(s):  
M. Bockstedte ◽  
A. Marini ◽  
Adam Gali ◽  
Oleg Pankratov ◽  
A. Rubio

Defect signatures, such as deep level positions, hyperfine parameters, local vibrational modes and optical transitions characterize a defect and enable the identification of defect centers. This identification is a key to an understanding of complex phenomena like the defect kinetics. Albeit density functional theory enabled the identification of several defects and their kinetic properties, a new approach is needed to address the optical excitation of defect. Within a quasiparticle theory and taking into account excitonic effects we analyze the excited states of VC +.


Synlett ◽  
2019 ◽  
Vol 31 (02) ◽  
pp. 158-164 ◽  
Author(s):  
Leticia Chavelas-Hernández ◽  
Jonathan R. Valdéz-Camacho ◽  
Luis G. Hernández-Vázquez ◽  
Blanca E. Dominguez-Mendoza ◽  
María G. Vasquez-Ríos ◽  
...  

The chemical shifts of protons depend not only on the properties of the solute molecule but also on the medium in which the solute resides. A series of β-lactams with various substitution patterns were synthesized to study aromatic-solvent-induced shifts (ASISs) in chloroform and benzene by using 1H NMR spectroscopy. The results agreed with those obtained by theoretical density functional theory calculations. The protons of the β-lactam ring are the most affected by the ASIS effect, and they tend to overlap due to the anisotropic effect of benzene.


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