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Topic Review
Electron-Beam Damage Mechanisms and Strategies in MOFs
Metal–organic frameworks (MOFs), composed of metal nodes and inorganic linkers, are promising for a wide range of applications due to their unique periodic frameworks. Understanding structure–activity relationships can facilitate the development of new MOFs. Transmission electron microscopy (TEM) is a powerful technique to characterize the microstructures of MOFs at the atomic scale. In addition, it is possible to directly visualize the microstructural evolution of MOFs in real time under working conditions via in situ TEM setups. Although MOFs are sensitive to high-energy electron beams, much progress has been made due to the development of advanced TEM.
  • 1.0K
  • 02 Jun 2023
Topic Review
Halide Segregation in Mixed Halide Perovskites
Metal halide perovskites (MHPs) has splendid optoelectronic properties and ease of processing, enabling efficiently fabricating high-performance photovoltaic devices with low-cost. MHPs are easy preparation and processing, but also face inherent instability issues, such as ion migration, halide segregation, phase transition and degradation.
  • 1.0K
  • 04 Mar 2022
Topic Review
Ternary Al–Ni–Er System
Al–Ni–Er is an essential system in heat-resistant Al alloys. The aluminum-rich corner of this system, which has the most practical application significance. The phase equilibria of the Al–Ni–Er system are investigated via experiments and thermodynamic modeling. The isothermal sections of the Al-rich corner of this ternary system at 600 and 700 °C were determined through equilibrated alloys combined with scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and X-ray diffractometry (XRD).
  • 1.0K
  • 03 Nov 2023
Topic Review
Specification of Glazings for Façades
The correct specification of glazings for façades can reduce the energy consumption in buildings. The heat exchange occurs through transparent surfaces and radiation reaches the building as light and heat. Therefore, glazings significantly contribute to the heat transfer between outdoor and indoor spaces and act directly on daylighting and thermal comfort. The selection of glazings should be a careful process of evaluation and weighing of tradeoffs. Among the characteristics required for the specification of transparent materials, the spectrophotometric behavior is an important factor to be considered, as it enables improvements in the thermal and visual comfort of a building.
  • 999
  • 28 Jul 2021
Topic Review
Synthesis and Electron Doping of TiNCl
Layered metal nitride halides MNX (M = Ti, Zr, Hf; X = Cl, Br, I) have two polymorphs, including α- and β-forms, which have the FeOCl and SmSI structures, respectively. These compounds are band insulators and become metals and show superconductivity after electron doping by intercalating alkali metals between the layers. The superconductivity of β-form had been extensively characterized from decades ago, but it is not easy to consistently interpret all experimental results using conventional phonon-mediated Bardeen–Cooper–Schriefer mechanisms. The titanium compound TiNCl crystallizes only in the α-form structure. TiNCl also exhibits superconductivity as high as ~16 K after electron doping by intercalating metals and/or organic basis. It is important to compare the superconductivity of different M–N networks. However, α-form compounds are vulnerable to moisture, unlike β-form ones. The intercalation compounds are even more sensitive to humid air.
  • 986
  • 07 Jun 2022
Topic Review
Wire and Arc Additive Manufactured Materials Corrosion Behaviour
Wire and Arc Additive Manufacturing (WAAM) is a deposition rate process for the creation and/or repair of large structural metallic components. The non-equilibrium heating and cooling conditions associated with WAAM lead to the development of heterogenous microstructures. Although there is a large body of work focusing on the microstructure and mechanical properties of WAAM-fabricated components, assessment of the corrosion behaviour of alloys fabricated by WAAM is still in its infancy. Here, the body of knowledge associated with the corrosion behaviour of different WAAM-fabricated engineering alloys is presented and discussed. Future perspectives and potential research topics are also presented. This is the first work focusing on the corrosion of wire and arc additive manufactured materials.
  • 986
  • 18 Apr 2023
Topic Review
Radiopaque Crystalline, Non-Crystalline and Nanostructured Bioceramics
Radiopacity is sometimes an essential characteristic of biomaterials that can help clinicians perform follow-ups during pre- and post-interventional radiological imaging. Due to their chemical composition and structure, most bioceramics are inherently radiopaque but can still be doped/mixed with radiopacifiers to increase their visualization during or after medical procedures. The radiopacifiers are frequently heavy elements of the periodic table, such as Bi, Zr, Sr, Ba, Ta, Zn, Y, etc., or their relevant compounds that can confer enhanced radiopacity. Radiopaque bioceramics are also intriguing additives for biopolymers and hybrids, which are extensively researched and developed nowadays for various biomedical setups. 
  • 973
  • 04 Nov 2022
Topic Review
Antimicrobial Coatings with Metal and Metal Oxide Nanoparticles
Antimicrobial coatings are utilized in the surface modification of yarns and materials designed for use in medical and dental applications. Various physical and chemical methods are employed to create these coatings, ensuring the development of efficient, homogeneous, and uniform layers on diverse surfaces and materials. For these coatings to be effective, they must incorporate active compounds that can combat a wide array of microorganisms, including those that have developed resistance to antibiotics. Examples of such active compounds include metallic nanoparticles such as silver, copper, and gold, as well as nanoparticles of metal oxides such as zinc, titanium, and aluminum. Upon the application of these coatings to medical materials, extensive testing and characterization procedures are undertaken, which will be thoroughly detailed in this entry. It is crucial to emphasize that the absence of proper characterization and testing of nanoparticles in antimicrobial coatings could lead to the absence of standards, norms, or procedures necessary to safeguard human health and the environment. Despite their widespread application in the medical field, concerns have been raised regarding the potential toxicity of nanoparticles to living organisms.
  • 953
  • 03 Nov 2023
Topic Review
Stress Corrosion Cracking of Copper–Nickel Alloys
Under the combination of certain corrosive ions and stress, Cu-Ni alloys may experience severe stress corrosion cracking (SCC), which causes premature failure and hinders their further applications as crucial construction materials in various engineering fields.
  • 952
  • 13 Oct 2023
Topic Review
Cellular Solid Materials
Cellular solids are materials made up of cells with solid edges or faces that are piled together to fit a certain space. These materials are already present in nature and have already been utilized in the past. Some examples are wood, cork, sponge and coral. New cellular solids replicating natural ones have been manufactured, such as honeycomb materials and foams, which have a variety of applications because of their special characteristics such as being lightweight, insulation, cushioning and energy absorption derived from the cellular structure. Cellular solids have interesting thermal, physical and mechanical properties in comparison with bulk solids: density, thermal conductivity, Young’s modulus and compressive strength. This huge extension of properties allows for applications that cannot easily be extended to fully dense solids and offers enormous potential for engineering creativity. Their Low densities allow lightweight and rigid components to be designed, such as sandwich panels and large portable and floating structures of all types. Their low thermal conductivity enables cheap and reliable thermal insulation, which can only be improved by expensive vacuum-based methods. Their low stiffness makes the foams ideal for a wide range of applications, such as shock absorbers. Low strengths and large compressive strains make the foams attractive for energy-absorbing applications. Their main properties, applications (real and potential) and recent developments are presented, summarized and discussed.
  • 937
  • 17 Nov 2023
Topic Review
Low-Dimensional Photocatalysts for CO2 Conversion
The ongoing energy crisis and global warming caused by the massive usage of fossil fuels and emission of CO2 into atmosphere continue to motivate researchers to investigate possible solutions. The conversion of CO2 into value-added solar fuels by photocatalysts has been suggested as an intriguing solution to simultaneously mitigate global warming and provide a source of energy in an environmentally friendly manner. There has been considerable effort for nearly four decades investigating the performance of CO2 conversion by photocatalysts, much of which has focused on structure or materials modification. In particular, the application of low-dimensional structures for photocatalysts is a promising pathway. Depending on the materials and fabrication methods, low-dimensional nanomaterials can be formed in zero dimensional structures such as quantum dots, one-dimensional structures such as nanowires, nanotubes, nanobelts, and nanorods, and two-dimensional structures such as nanosheets and thin films. These nanostructures increase the effective surface area and possess unique electrical and optical properties, including the quantum confinement effect in semiconductors or the localized surface plasmon resonance effect in noble metals at the nanoscale. 
  • 925
  • 29 Apr 2021
Topic Review
Improved and Innovative Accident-Tolerant Nuclear Fuel Materials
Since 2011, there has been an international effort to evaluate the behavior of newer fuel rod materials for the retrofitting of existing light water reactors (LWR). These materials include concepts for the cladding of the fuel and for the fuel itself. The materials can be broadly categorized into evolutionary or improved existing materials and revolutionary or innovative materials. The purpose of the newer materials or accident-tolerant fuels (ATF) is to make the LWRs more resistant to loss-of-coolant accidents and thus increase their operation safety. The benefits and detriments of the three main concepts for the cladding are discussed.
  • 923
  • 11 Sep 2023
Topic Review
Polylactic Acid Biopolymer in Multi-Material Additive Manufacturing
3D printing is a revolutionary additive manufacturing method that enables rapid prototyping and design flexibility. A variety of thermoplastic polymers can be used in printing. As it is necessary to reduce the consumption of petrochemical resources, alternative solutions are being researched, and the interest in using bioplastics and biocomposites is constantly growing. Multi-material printing using polymers is the subject of research led by many scientists worldwide. The number of materials for printing is practically unlimited, especially considering the independent production of filaments or their modification, which is becoming easier and is more available for research institutions. One popular and economic printing technique using polymers is the fused deposition modeling (FDM)/Fused Filament Fabrication (FFF) technology.
  • 913
  • 25 Aug 2022
Topic Review
Austenite in Advanced High Strength Steels
Advanced high strength steels (AHSS) are developed to reduce vehicle weight without sacrificing passenger safety. The newly developed AHSS frequently incorporates the austenite as the intrinsic component with large amount and good stability, which is realized by carefully designed alloying elements and thermo-mechanical processing. 
  • 910
  • 28 Mar 2022
Topic Review
Manipulating Nucleation Potency of Substrates by Interfacial Segregation
During solidification of metallic materials, heterogeneous nucleation occurs on substrates, either endogenous or exogenous. The potency of the substrates for nucleation is mainly dependent upon the atomic arrangements on the substrate surface, which are affected by the lattice misfit between the substrate and the nucleated solid, the surface roughness at atomic scale, and the chemical interaction between the substrates and the melt. Extensive examinations on metal/substrate (M/S) interfaces at atomic scale by the state-of-the-art aberration (Cs) corrected STEM and associated EDS and EELS have shown that alloying elements in liquid melts tend to segregate at the interfaces, leading to the formation of various 2-dimensional compounds (2DCs) or 2-dimensional solutions (2DSs), depending upon segregation behavior of the elements. For instance, Al3Ti 2DC and Ti2Zr 2DC at the Al/TiB2 interface, Y2O3 2DC at the Mg/MgO interface, and a Si-rich 2DS layer at Al-Si/TiB2 interface have been identified. Such interfacial segregations significantly affect nucleation potency of the substrates, resulting in either promoting or impeding the heterogeneous nucleation process during solidification.
  • 872
  • 21 Oct 2022
Topic Review
Additive Manufacturing (3D/4D Printing) Technologies
The scientific community is and has constantly been working to innovate and improve the available technologies in our use. In that effort, three-dimensional (3D) printing was developed that can construct 3D objects from a digital file. Three-dimensional printing, also known as additive manufacturing (AM), has seen tremendous growth over the last three decades, and in the last five years, its application has widened significantly. Three-dimensional printing technology has the potential to fill the gaps left by the limitations of the current manufacturing technologies, and it has further become exciting with the addition of a time dimension giving rise to the concept of four-dimensional (4D) printing, which essentially means that the structures created by 4D printing undergo a transformation over time under the influence of internal or external stimuli.
  • 870
  • 16 Jan 2024
Topic Review
Dye-Sensitized Solar Cells Nanostructures and Natural Colorants
The history of sensitized cells began with the pioneering work of Brian O’Regan and Michael Grätzel, on the promising applications of nanosized TiO2porous film electrodes in dye-sensitized solar cells (DSSC); these devices convert solar energy into electricity through the photoelectric effect. The first devices worked with ruthenium-based dyes and their efficiencies were around 10%. DSSCs are low cost to manufacture, eco-friendly, and are considered to have a high photon-to-electricity conversion efficiency, so they soon became an intense field of research.
  • 869
  • 08 Nov 2021
Topic Review
Measuring Physical Properties of Electrospun Nanofiber Mats
Electrospun nanofiber mats are nowadays often used for biotechnological and biomedical applications, such as wound healing or tissue engineering. 
  • 868
  • 10 May 2023
Topic Review
Natural Disordered sp2 Carbon
The progress in the practical use of glassy carbon materials has led to a considerable interest in understanding the nature of their physical properties. The electrophysical properties are among the most demanded properties. In nature, in the course of geological processes, disordered sp2 carbon substances were formed, the structure of which is in many respects similar to the structure of glassy carbon and black carbon, and the electrical properties are distinguished by a high-energy storage potential and a high efficiency of shielding electromagnetic radiation.
  • 859
  • 18 Nov 2022
Topic Review
Applications of Recycled and Crushed Glass
Glass is a substance that is present in most houses since glass-based items are made and consumed in relatively high quantities. This has led to the buildup of glass in concerning quantities all over the world, which is a problem for the environment. It is well known that glass has several advantageous physiochemical features that qualify it as an appropriate material for use in the construction industry as an aggregate. The features include being non-biodegradable, resistant to chemical assault, having low water absorption, having high hydraulic conductivity, having temperature-dependent ductility, having alterable particle gradation, and having a wide availability in a variety of forms and chemical compositions. 
  • 859
  • 29 Dec 2023
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