You're using an outdated browser. Please upgrade to a modern browser for the best experience.
Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort by:
Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)
Filter:
All Topic Review Biography Peer Reviewed Entry Video Entry
Topic Review
Angle-Resolved Photoemission Spectroscopy (ARPES)
Angle-resolved photoemission spectroscopy (ARPES) is a vital technique in which spectra are collected from both the energy and momentum of photoemitted electrons and is indispensable for investigating the electronic band structure of solids. 
  • 9.8K
  • 08 Dec 2020
Topic Review
Inelastic Neutron Scattering
Inelastic neutron scattering (INS) is a spectroscopy based on the energy analysis of neutrons after they have been scattered by a sample. A detected energy transfer can be related to a physical interaction of the corresponding atoms with their environment. An energy transfer of several meVs typically arises from vibrations of atoms. Thus, INS provides an amplitude-of-motion and neutron incoherent cross section weighted phonon density of states.  Given the much higher incoherent scattering cross section of hydrogen relative to that of all other elements, INS is particular sensitive to hydrogen based vibrations. The method is widely used in condensed matter physics and solid state chemistry, because the vibrational properties of matter define various physical properties such as the heat capacity. If used as a fingerprint method, INS can be used to characterize chemical bonds both in the bulk as well as on the surface.
  • 9.4K
  • 30 Oct 2020
Topic Review
Materials Science, Glasses
Glasses are solid amorphous materials which transform into liquids upon heating through the glass transition. The International Commission on Glass defines glass as a state of matter, usually produced when a viscous molten material is cooled rapidly to below its glass transition temperature, with insufficient time for a regular crystal lattice to form. The solid-like behaviour of glasses is separated from the liquid-like behaviour at higher temperatures by the glass transition temperature, Tg. The IUPAC Compendium on Chemical Terminology defines glass transition as a second order transition in which a supercooled melt yields, on cooling, a glassy structure. It states that below the glass-transition temperature the physical properties of glasses vary in a manner similar to those of the crystalline phase. Moreover, it is deemed that the bonding structure of glasses has the same symmetry signature in terms of Hausdorff-Besikovitch dimensionality of chemical bonds as for the crystalline materials. 
  • 6.2K
  • 09 May 2024
Topic Review
Boron-Doped Diamond
Boron-doped diamond (BDD) acts as an excellent p-type conductive material for high-temperature, high-power and radiation-proof photoelectronic devices with its large band gap at room temperature (5.47 eV) and high thermal conductivity.
  • 3.6K
  • 06 Jan 2021
Topic Review
Liquid Crystal Aided Nanotechnology/Nanoscience
The research field of liquid crystals and their applications is recently changing from being largely focused on display applications and optical shutter elements in various fields, to quite novel and diverse applications in the area of nanotechnology and nanoscience. Functional nanoparticles, such as ferroelectric and magnetic particles, have recently been used to a significant extent to modify the physical properties of liquid crystals. Also, intriguing photonic functionalities can be realized by adding nanoparticles such as quantum dots, metal particles, semiconductors, etc. into liquid crystals. The self-organization of liquid crystal molecules is exploited to used as order templates to orient nanoparticles. Similarly, anisodiametric nanoparticles such as rods, nanotubes and flakes are shown to form lyotropic liquid crystal phases in the presence of isotropic host solvents at a certain concentration.
  • 3.1K
  • 27 Oct 2020
Topic Review
Permanent Magnets and How They Dictated History
The most efficient electric motor is a permanent-magnet synchronous motor. Their efficiency makes them popular for drive motors, power steering, stop-start motors, and regenerative braking generators. These motors use permanent magnets based on rare-earth elements (REEs), in particular neodymium-iron-boron (Nd-Fe-B) and samarium-cobalt (Sm-Co), because of their high maximum energy product (BH)max (a measure of the magnet’s performance), which is needed for the high efficiency and the high resistance to demagnetization. But there are still some challenges and gaps in their performance and application.
  • 2.7K
  • 27 Feb 2024
Topic Review
Avalanche Photodiodes and Silicon Photomultipliers of Non-Planar Designs
Conventional designs of an avalanche photodiode (APD) have been based on a planar p–n junction since the 1960s. APD developments have been driven by the necessity to provide a uniform electric field over the active junction area and to prevent edge breakdown by special measures. Most modern silicon photomultipliers (SiPM) are designed as an array of Geiger-mode APD cells based on planar p–n junctions. Modern Silicon Photomultipliers (SiPM) are designed as an array of Geiger-mode APD cells based on planar p-n junctions. However, the planar design faces an inherent trade-off between photon detection efficiency and dynamic range due to loss of an active area at the cell edges. Non-planar designs of APDs and SiPMs have also been known since the development of spherical APD (1968), Metal-Resistor-Semiconductor APD (1989), and Micro-well APD (2005). Recent development of Tip Avalanche Photodiode (2020) based on the spherical p-n junction eliminates the trade-off, outperforms the planar SiPMs in the photon detection efficiency, and opens new opportunities for SiPM improvements. Moreover, the latest developments of APDs based on electric field-line crowding and charge-focusing topology with quasi-spherical p-n junctions (2019–2023) show promising functionality in linear and Geiger operating modes.
  • 2.6K
  • 27 Jun 2023
Topic Review
Cryotropic Gelation and Macroporous Scaffolds
Cryogels obtained by the cryotropic gelation process are macroporous hydrogels with a well-developed system of interconnected pores and shape memory. Biodegradable cryogels have been prepared from natural polymers (biopolymers) and synthetic polymers with biodegradable/bioresponsive bonds containing bio-resembling or artificial units. The cryogels could be composed of one type of polymer or a combination of different materials. Polymers from natural origins (plants or animals) attract considerable attention for their intrinsic biocompatibility and potential ability to mimic ECM, favoring cell-matrix interactions for tissue-engineering and regeneration.
  • 2.4K
  • 12 Jul 2021
Topic Review
Ferroelastic Twinning in Minerals
Ferroelastic twinning in minerals is a very common phenomenon. The twin laws follow simple symmetry rules and they are observed in minerals, like feldspar, palmierite, leucite, perovskite, and so forth. The major discovery over the last two decades was that the thin areas between the twins yield characteristic physical and chemical properties, but not the twins themselves. Research greatly focusses on these twin walls (or ‘twin boundaries’); therefore, because they possess different crystal structures and generate a large variety of ‘emerging’ properties. Research on wall properties has largely overshadowed research on twin domains. 
  • 2.4K
  • 15 Jun 2021
Topic Review
Optical Properties of Plasmonic Metal Nanoparticles
Plasmonic phenomena and materials have been extensively investigated for a long time and gained popularity in the last few years, finding in the design of the biosensors platforms promising applications offering devices with excellent performances. Hybrid systems composed of graphene, or other 2D materials, and plasmonic metal nanostructures present extraordinary optical properties originated from the synergic connection between plasmonic optical effects and the unusual physicochemical properties of 2D materials, thus improving their application in a broad range of fields. 
  • 2.3K
  • 08 Jul 2022
Topic Review
Control and Upgradation of Indoor Air Quality
Due to increasing health and environmental issues, indoor air quality (IAQ) has garnered much research attention with regard to incorporating advanced clean air technologies. Various physicochemical air treatments have been used to monitor, control, and manage air contaminants, such as monitoring devices (gas sensors and internet of things-based systems), filtration (mechanical and electrical), adsorption, UV disinfection, UV photocatalysts, a non-thermal plasma approach, air conditioning systems, and green technologies (green plants and algae).
  • 2.2K
  • 24 Feb 2023
Topic Review
N-Type Organic Semiconductors
This work was intended to enlarge the gates toward green organic technologies at room temperature, searching for new types of semiconductors with low toxicity and simple molecular organization. In our previous studies, para-aminobenzoic acid was used to construct a p-type green semiconductor. A non-toxic organic compound, acting as an electron donor, is sulpho-salicylic acid. SSA can be efficiently attached to the external shell of a ferrite (Fe3O4) nanocore, providing Fe3O4–SSA nanoparticles. This is a N-Type Organic Semiconductor - made by green technologies and used to construct a simple thin film transistor. 
  • 2.1K
  • 22 Oct 2020
Topic Review
Calculation of the transition temperature of superconducting elements
Using the Roeser-Huber formalism, we establish a non-trivial relation between the crystal structure and the transition temperature, Tc, to the superconducting state. By means of this relation, we can calculate Tc for practically all superconducting elements quite accurately within a small error margin. It is shown that this works well also for polymorphic elements and elements under pressure. Furthermore, the Roeser-Huber formalism implies that all calculated data fall on a common line with the slope m1 = h2/(2πkB) = 5.061 × 10−45 m2 kg K, when plotting log(Σ((2x)-2n1-1ML-1))-1 versus 1/Tc, which can be employed as a test when predicting Tc of unknown superconductors.
  • 2.0K
  • 21 Jun 2023
Topic Review
Low-Frequency Plasma-Enhanced Chemical Vapor Deposition (LFPECVD)
The low-frequency plasma-enhanced chemical vapor deposition in cyclohexane atmospheres is an easy-to-implement technology for carbon-based coatings deposition. LFPECVD (like RF PECVD), which has the capacity to be implemented in any scale, is widely used in industry.
  • 2.0K
  • 21 Oct 2021
Topic Review
Cellulose and Microfluidics
Cellulose, a linear polysaccharide, is the most common and renewable biopolymer in nature.
  • 2.0K
  • 10 Feb 2022
Topic Review
Lipid Bilayers on Silicon Substrates
Artificial membranes are models for biological systems that are important for several applications. In the present entry we talk about artificial membranes such as supported lipid bilayers (SLB) and ways to self- assemble them. We mainly focus on the results of a new dry evaporation process in high vacuum, i.e., physical vapor deposition, to make samples of dipalmitoylphosphatidylcholine (DPPC) on silicon substrates. We have characterized the main phase transitions and adhesion of our SLBs using high-resolution ellipsometry and AFM techniques. The finding of this new SLB fabrication approach is relevant for the understanding the interaction of lipid bilayers in contact with surfaces in dry environments, with the aim to develop new kinds of lab-on-chip bionanosensors. This discovery is especially relevant in the context of the viability of organisms covered with lipid bilayer structures. An example of this kind of interaction occurs between bilayer-protected viruses, e.g., corona viruses, and solid surfaces, allowing the virus to stay active during long periods of time. The prolonged stability of SLBs on dry SiO2/Si substrates detected in our research can explain the long-term stability of some viruses deposited or adsorbed on dry surfaces, including the SARS-CoV-2 virus. 
  • 1.9K
  • 03 Nov 2020
Topic Review
Interactions between Atmospheric Oxygen and MoS2 Crystals
MoS2 belongs to a class of transition metal dichalcogenides (TMDCs). TMDCs share a common formula MeX2, where Me is a transition metal element from group four (Ti, Zr, Hf), five (V, Nb or Ta) or six (Mo, W), and X is a chalcogen (S, Se or Te). Their crystalline structure comprises an inner Me layer sandwiched by two X layers. Herein, thermal oxidation of the microscopic MoS2 flakes is reviewed. An impact of relative humidity is also mentioned.
  • 1.8K
  • 26 Oct 2021
Topic Review
Spins in Semiconductor Nanoparticles
- Spin-dependent phenomena in semiconductors are analyzed starting from a theory of the dynamic nuclear polarization via numerous insightful findings in the realm of characterization and control through the nuclear spin polarization in nanoparticles and their aggregates into microparticles as potential contrast agents for magnetic resonance imaging (MRI) applications.  - Electron spin-dependent process of the photosensitized generation of singlet oxygen in porous silicon (Si) for photodynamic therapy application and design of Si-based nanoparticles with electron spin centers for MRI contrasting for cancer theranostics are discussed.  
  • 1.8K
  • 12 Jan 2021
Topic Review
Rigid Templates for Fabricating 3D Nanostructures
Rigid templates are defined as opposed to soft templates, and are made of hard materials. Rigid templates have good chemical stability and mechanical rigidity, which are mostly used for the fabrication of nanostructure arrays. A wide choice of rigid templates is available, such as silicon, anodic aluminum oxide, carbon, silica spheres, biological structures, and so forth.
  • 1.7K
  • 14 Jun 2022
Topic Review
Ferromagnetic
Ferromagnetism is a phenomenon whereby a substance can become a permanent magnet or strongly reacts to a magnetic field. 
  • 1.6K
  • 27 Apr 2022
  • Page
  • of
  • 3
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of COVID-19
Encyclopedia of Engineering
Encyclopedia of Social Sciences
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Academic Video Service
Feedback