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JournalISSN: 1661-819X

Advances in Science and Technology 

Trans Tech Publications
About: Advances in Science and Technology is an academic journal published by Trans Tech Publications. The journal publishes majorly in the area(s): Ceramic & Materials science. It has an ISSN identifier of 1661-819X. Over the lifetime, 2492 publications have been published receiving 8898 citations. The journal is also known as: AST.


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Journal ArticleDOI
TL;DR: The current status of hydrothermal technology for inorganic powders with respect to types of materials prepared, ability to control the process, and use in commercial manufacturing is discussed in this article.
Abstract: This paper briefly reviews hydrothermal synthesis of ceramic powders and shows how understanding the underlying physico-chemical processes occurring in the aqueous solution can be used for engineering hydrothermal crystallization processes Our overview covers the current status of hydrothermal technology for inorganic powders with respect to types of materials prepared, ability to control the process, and use in commercial manufacturing General discussion is supported with specific examples derived from our own research (hydroxyapatite, PZT, 􀄮-Al2O3, ZnO, carbon nanotubes) Hydrothermal crystallization processes afford excellent control of morphology (eg, spherical, cubic, fibrous, and plate-like) size (from a couple of nanometers to tens of microns), and degree of agglomeration These characteristics can be controlled in wide ranges using thermodynamic variables, such as reaction temperature, types and concentrations of the reactants, in addition to non-thermodynamic (kinetic) variables, such as stirring speed Moreover, the chemical composition of the powders can be easily controlled from the perspective of stoichiometry and formation of solid solutions Finally, hydrothermal technology affords the ability to achieve cost effective scale-up and commercial production

193 citations

Journal ArticleDOI
TL;DR: In this article, the similarities and main differences between the two types of magnetically controllable fluids are outlined and exemplified in the paper and chemical synthesis and structural characterization of magnetizable fluids for engineering and biomedical applications are thoroughly discussed.
Abstract: Composition, synthesis and structural properties of ferrofluids and magnetorheological fluids are reviewed and compared. The similarities and main differences between the two types of magnetically controllable fluids are outlined and exemplified in the paper. Chemical synthesis and structural characterization of magnetizable fluids for engineering and biomedical applications are thoroughly discussed.

85 citations

Journal Article
TL;DR: In this article, the decay time of nanocrystalline ZnS:Mn 2+ was investigated and it was shown that the defect-related emission of the Mn 2+ impurity is not responsible for the decay of the 4 T 1 -A 1 transition.
Abstract: In recent publications it was reported that doped semiconductor nanoparticles can yield both high luminescence efficiencies and a spectacular lifetime shortening, which suggested that doped semiconductor nanoparticles form a new class of luminescent materials for various applications. From lifetime measurements and time-resolved spectroscopy we conclude that the Mn 2+ emission of nanocrystalline ZnS:Mn 2 + does not show a spectacular shortening of the decay time upon decreasing particle size as reported earlier. The luminescence of nanocrystalline ZnS:Mn 2 + indeed has a short decay time (- 100 ns), but also shows a long ms range decay time. The short decay time originates from a defect related emission of ZnS, and not from the decay of the 4 T 1 -A 1 transition of the Mn 2+ impurity as suggested by other authors. The 4 T 1 - 6 A 1 transition of the Mn 2+ has a 'normal' decay of about 1.9 ms. Based on our observations, we conclude that doped semiconductor nanoparticles do not form a new class of luminescent materials, combining a high efficiency with a short (ns) decay time.

81 citations

Journal ArticleDOI
TL;DR: Thermally, light-, and magnetically induced shape-memory polymers, that were developed especially for minimally invasive surgery and other biomedical applications, are presented and triple-shape polymers will be introduced, that have the capability to perform two subsequent shape changes, enabling more complex movements of a polymeric material.
Abstract: Most polymers used in clinical applications today are materials that have been developed originally for application areas other than biomedicine. On the other side, different biomedical applications are demanding different combinations of material properties and functionalities. Compared to the intrinsic material properties, a functionality is not given by nature but result from the combination of the polymer architecture and a suitable process. Examples for functionalities that play a prominent role in the development of multifunctional polymers for medical applications are biofunctionality (e.g. cell or tissue specificity), degradability, or shape-memory functionality. In this sense, an important aim for developing multifunctional polymers is tailoring of biomaterials for specific biomedical applications. Here the traditional approach, which is designing a single new homo- or copolymer, reaches its limits. The strategy, that is applied here, is the development of polymer systems whose macroscopic properties can be tailored over a wide range by variation of molecular parameters. The Shape-memory capability of a material is its ability to trigger a predefined shape change by exposure to an external stimulus. A change in shape initiated by heat is called thermally-induced shape-memory effect. Thermally, light-, and magnetically induced shape-memory polymers will be presented, that were developed especially for minimally invasive surgery and other biomedical applications. Furthermore triple-shape polymers will be introduced, that have the capability to perform two subsequent shape changes. Thus enabling more complex movements of a polymeric material.

76 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that the incorporation of thin layers made of an active medium adjacently to the core layer of a negative-refractive-index waveguide can completely remove dissipative losses in a slow-light regime where the effective index of the guided wave is negative.
Abstract: We review recent theoretical and experimental breakthroughs in the realm of slow and stopped light in structured photonic media featuring negative electromagnetic parameters (permittivity/permeability and/or refractive index). We explain how and why these structures can enable complete stopping of light even in the presence of disorder and, simultaneously, dissipative losses. Using full-wave numerical simulations we show that the incorporation of thin layers made of an active medium adjacently to the core layer of a negative-refractive-index waveguide can completely remove dissipative losses – in a slow-light regime where the effective index of the guided wave is negative.

75 citations

Performance
Metrics
No. of papers from the Journal in previous years
YearPapers
2023193
2022138
2021128
202010
20181
2016112