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[en] It is suggested that the existing classification of polytype structures of zinc sulfide be supplemented with an additional criterion: the characteristic of regular point systems (Wyckoff positions) including their type, number, and multiplicity. The consideration of the Wyckoff positions allowed the establishment of construction principles of known polytype series of different symmetries and the systematization (for the first time) of the polytypes with the same number of differently packed layers. the classification suggested for polytype structures of zinc sulfide is compact and provides a basis for creating search systems. The classification table obtained can also be used for numerous silicon carbide polytypes. 8 refs., 4 tabs
[en] In this paper, we present an empirical expression relating to the electronic polarizability α (A3) for binary and ternary tetrahedral semiconductors with the product of ionic charges (Z1 and Z2) and nearest-neighbor distance d (A). The electronic polarizability of these compounds exhibits a linear relationship when plotted on a log-log scale against the nearest-neighbor distance d (A), but falls on different straight lines according to the ionic charge product of the compounds. We have applied the proposed relation to zinc blende and complex structured solids and found a better agreement with experimental data compared to the values evaluated by earlier researchers.
[en] The effect of sulfide treatment on the electrical, structural and photoluminescent properties of ZnS films is investigated. The dependences of crystal quality and luminescence on sulfide treatment are found. The crystallinity can be enhanced while following sulfide treatment. Such an improvement indicates the reduced number of sulfur vacancies (VS) as a result of the adsorption (incorporation) of the sulfur atoms during the sulfide treatment process. A correlation between the VS density and sulfide treatment is identified for providing a guide to tune the photoluminescence spectra and p-type conductivity for ZnS samples.
[en] After a short discussion of high field electroluminescence the manufacture of a.c. driven Zns:Mn thin film devices is described. The two insulating layers consist of sputtered Al2O3, the encapsulated active layer is obtained by evaporation in vacuo - during this process the water vapor partial pressure should be kept as low as possible. The voltage-brightness relation makes these devices suitable for multiplexing. The maximum luminance that can be achieved and the luminous efficiency are 3000 cd/m2 and 0.5 lm/W respectively. Improvements still have to be made as far as the long time stability of the displays is concerned. (orig.)
[en] ZnS:Mn is one of the brightest mechanoluminescent (ML) materials known, which makes it a prime candidate for use in Structural Health Monitoring (SHM) applications. For this work crystalline ZnS:Mn powder was embedded in a clear polyurethane (PU) matrix. The total emitted energy per unit solid angle per unit area, as well as the average radiance values of different samples are measured with a calibrated camera to determine the concentration and thickness of ZnS:Mn/PU for optimal emission. A trend is observed where emission from tensile loading appears stronger than that from compressive loading, and emission from fracture is stronger than that from plastic loading which itself is stronger than that from elastic loading. Also, the ML emissions by elastic and plastic loadings tend to increase with material thickness and ZnS:Mn concentration. Both tensile- and bending-induced fracture modes were tested. While for tensile fracture the emission is approximately independent of thickness and concentration, the emission accompanying an abrupt bending fracture increases with the ZnS:Mn concentration. This work presents a first quantitative absolute measurement of ML emission of ZnS:Mn, while also introducing the use of PU as potential host material, that can benefit many SHM and other applications.
[en] A sealed light source, containing zinc-sulphid phosphor activated by 1.85 GBq (50 mCi) 147Pm, was constructed. Its illuminating surface is 1 cm2. The structure of the light source and the technology of production are described in detail. After construction, the mechanical integrity, the exact sealing and the surface contamination of the source were controlled. Temperature, pressure and vibration tests were also carried out. The intensity of the light sources was determined by an in-house-developed equipment. The same tests were repeated 2.5 years later; based on this the working time of the light sources is estimated to be 10 years. (L.E.)
[en] Vickers microhardness of compacted nanoparticles of ZnS of average grain sizes 3-12 nm was studied for different compaction pressures. The hardness was found to increase rapidly with load for smaller values of the load and then to become practically independent of load. The microhardness was found to increase with increase in grain size showing inverse Hall-Petch relation in the present study.
[en] Extensive research work has been done in recent times to apply the triboluminescence (TL) phenomenon for damage detection in engineering structures. Of particular note are the various attempts to apply it in the detection of impact damages in composites and aerospace structures. This is because TL-based sensor systems have a great potential for wireless, in-situ and distributed (WID) structural health monitoring when fully developed. This review article highlights development and the current state-of-the-art in the application of TL-based sensor systems. The underlying mechanisms believed to be responsible for triboluminescence, particularly in zinc sulfide manganese, a highly triboluminescent material, are discussed. The challenges militating against the full exploitation and field application of TL sensor systems are also identified. Finally, viable solutions and approaches to address these challenges are enumerated. - Highlights: → The underlying mechanisms believed to be responsible for triboluminescence. → State-of-the-art in the development and application of TL-based sensor systems. → The challenges militating against the full exploitation and field application of TL sensor systems are identified. → Viable solutions and approaches to address these challenges are enumerated.