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Topic Review
Radiation-Balanced Lasers
Radiation-balanced lasers can provide lasing without detrimental heating of laser medium. This new approach to the design of optically pumped rare-earth (RE)-doped solid-state lasers is provided by balancing the spontaneous and stimulated emission within the laser medium. It is based on the principle of anti-Stokes fluorescence cooling of RE-doped low-phonon solids.
  • 1.3K
  • 13 Sep 2021
Topic Review
Mid-Infrared Supercontinuum Generation in Fluoroindate Glass Fibers
Supercontinuum (SC) generation that leads to the emission of broadband radiation has been extensively studied. In particular, SC sources encompassing the wavelength range of 2–5 μm have attracted considerable interest in the last decade, and a continuous increase in the output power and spectrum width has been observed. To enable broadband and high-power SC generation, suitable nonlinear media combined with appropriate pump sources must be used, maintaining the output as spectrally flat. The emergence of specialty glass fibers, such as fluoroindate fibers, as well as the advances in fiber-based pulsed oscillators and amplifiers, have accelerated the development of high-power SC systems operating in the mid-infrared spectral band.
  • 1.3K
  • 11 Jun 2022
Topic Review
Fine-Grained Change Detection
Fine-grained change detection in sensor data is very challenging for artificial intelligence though it is critically important in practice. It is the process of identifying differences in the state of an object or phenomenon where the differences are class-specific and are difficult to generalise. As a result, many recent technologies that leverage big data and deep learning struggle with this task.
  • 1.3K
  • 12 Jul 2021
Topic Review
Technology for Science Education
The COVID-19 confinement has represented both opportunities and losses for education. Rarely before has any other period moved the human spirit into such discipline or submission—depending on one’s personal and emotional points of view. Both extremes have been widely influenced by external factors on each individual’s life path. Education in the sciences and engineering has encountered more issues than other disciplines due to specialized mathematical handwriting, experimental demonstrations, abstract complexity, and lab practices. 
  • 1.2K
  • 22 Sep 2021
Topic Review
All-d-Metal Heusler Alloys
A promising strategy, resulting in novel compounds with better mechanical properties and substantial magnetocaloric effects, is favoring the d–d hybridization with transition-metal elements to replace p–d hybridization. The term given to these materials is “all-d-metal”. 
  • 1.2K
  • 10 Feb 2023
Topic Review
SWCNTs in Magnetic Recording
Applications in magnet-recording devices rely on the combination and emergence of unique properties of single-walled carbon nanotubes (SWCNTs) and encapsulated materials. The entry “SWCNTs in magnetic recording” focuses on applications of filled SWCNTs in magnetic recording.
  • 1.2K
  • 11 Nov 2021
Biography
George Doundoulakis
George James Doundoulakis (October 19, 1921 – March 17, 2007) was a Greek American physicist and soldier who worked under British Intelligence during World War II with SOE agent Patrick Leigh Fermor, and then served with the OSS in Thessaly, Greece. He is known by his twenty-six US Patents in the fields of radar, electronics, and narrowband television. Doundoulakis is best remembered for the
  • 1.2K
  • 11 Nov 2022
Topic Review
High-Precision Trace Hydrogen Sensing
Despite its growing importance in the energy generation and storage industry, the detection of hydrogen in trace concentrations remains challenging, as established optical absorption methods are ineffective in probing homonuclear diatomics. Besides indirect detection approaches using, e.g., chemically sensitized microdevices, Raman scattering has shown promise as an alternative direct method of unambiguous hydrogen chemical fingerprinting. 
  • 1.2K
  • 13 Jun 2023
Topic Review
Site Directed Spin Labeling
Site-directed spin labeling (SDSL) is a molecular biology technique in which paramagnetic spin labels are incorporated into the specific site of bio-macromolecules for investigation of structure and dynamic properties using electron paramagnetic resonance (EPR) spectroscopy. In SDSL, all native nondisulfide bonded cysteines are eliminated by changing them with another amino acid such as serine or an alanine. A unique cysteine residue is then incorporated into a recombinant protein using site-directed mutagenesis technique, and further reacted with sulfhydryl-specific nitroxide reagent to covalently generate a stable spin label side-chain. The development of SDSL approaches extended the application of EPR to almost any biological systems. Site-directed spin labeling  (SDSL) combined with EPR spectroscopy can provide structural dynamics of spin label side-chain, solvent accessibility, solvent polarity, and intra- or intermolecular distances between two spin labels of macromolecules.
  • 1.2K
  • 27 Apr 2021
Topic Review
SWCNTs in Nanoelectronics
The unique tailored electronic properties of single-walled carbon nanotubes (SWCNTs) render them promising platforms for nanoelectronics applications.
  • 1.2K
  • 09 Nov 2021
Topic Review
Source/Drain Ohmic Contact with β-Ga2O3
β-Ga2O3, with excellent bandgap, breakdown field, and thermal stability properties, is considered to be one of the most promising candidates for power devices including field-effect transistors (FETs) and for other applications such as Schottky barrier diodes (SBDs) and solar-blind ultraviolet photodetectors. Ohmic contact is one of the key steps in the β-Ga2O3 device fabrication process for power applications. 
  • 1.2K
  • 23 Oct 2023
Topic Review
Magnetic Force Microscopy on Nanofibers
Magnetic force microscopy is a magnetic characterization method of samples usually with a maximum of a few ten nanometers surface roughness. It works by measuring an atomic force microscopy (AFM) image of the surface topography of a sample, followed by lifting the probe to avoid short-range van der Waals interactions between the tip and sample and instead measuring the long-range magnetic interactions. In addition to this simplest form of magnetic force microscopy (MFM), there are more sophisticated ones, including frequency-modulated Kelvin probe force MFM, dynamic magneto-electric force microscopy, phase-locked loop methods, and even measurements in different environments, e.g., in liquids, that have been shown.
  • 1.2K
  • 10 Nov 2021
Topic Review
Magnetoelectric Magnetic Field Sensors
One of the new materials that have attracted wide attention of researchers are magnetoelectric (ME) composites. Great interest in these materials is due to their properties associated with the transformation of electric polarization/magnetization under the influence of external magnetic/electric fields and the possibility of their use to create new devices. ME magnetic field sensors based on the widely used structures Terfenol—PZT/PMN-PT,Metglas—PZT/PMN-PT, and Metglas—Lithium niobate, among others, are considered as the first applications of the ME effect in technology. Estimates of the parameters of ME sensors are given, and comparative characteristics of magnetic field sensors are presented. Taking into account the high sensitivity of ME magnetic field sensors, comparable to superconducting quantum interferencedevices (SQUIDs), this entry discuss the areas of their application.
  • 1.2K
  • 08 Feb 2023
Topic Review
Laser Interference Lithography
Laser interference lithography (LIL) is a technique that allows for the simple, flexible, and rapid fabrication of high-resolution periodic structures over large areas without the use of masks. Different interference conditions can produce a wide range of light fields. When an LIL system is used to expose the substrate, a variety of periodic textured structures, such as periodic nanoparticles, dot arrays, hole arrays, and stripes, can be produced. The LIL technique can be used not only on flat substrates, but also on curved or partially curved substrates, taking advantage of the large depth of focus.
  • 1.1K
  • 26 Jun 2023
Topic Review
Recombination Mediators Proteins
The recombination mediator proteins (RMPs) are ubiquitous and play a crucial role in genome stability. RMPs facilitate the loading of recombinases like RecA onto single-stranded (ss) DNA coated by single-strand binding proteins like SSB.
  • 1.1K
  • 22 Apr 2021
Topic Review
Radiographic Imaging with Muons
Radiographic imaging with muons, also called Muography, is based on the measurement of the absorption of muons, generated by the interaction of cosmic rays with the earth’s atmosphere, in matter. Muons are elementary particles with high penetrating power, a characteristic that makes them capable of crossing bodies of dimensions of the order of hundreds of meters. 
  • 1.1K
  • 08 Dec 2021
Topic Review
Geant4-DNA Simulation Toolkit
The Geant4-DNA low energy extension of the Geant4 Monte Carlo (MC) toolkit is a continuously evolving MC simulation code permitting mechanistic studies of cellular radiobiological effects. Geant4-DNA considers the physical, chemical, and biological stages of the action of ionizing radiation (in the form of x- and γ-ray photons, electrons and β±-rays, hadrons, α-particles, and a set of heavier ions) in living cells towards a variety of applications ranging from predicting radiotherapy outcomes to radiation protection both on earth and in space.
  • 1.1K
  • 19 Jan 2022
Topic Review
Bulk and Single Crystal Growth Progress of FBS
The new iron-based superconductor (FBS) has generated enormous interest in this direction, and many research activities are currently going on with various kinds of FBS. FBS was discovered in 2008 through F doped LaFeAsO, which crystallizes with a tetragonal layered ZrCuSiAs structure, and after that, many compounds have been discovered, most of which display superconductivity through suitable doping. FBS became the second high-Tc-superconducting family after cuprate superconductors and has been the subject of extensive research into their physical nature and application potential.
  • 1.1K
  • 14 Jan 2022
Topic Review
Graphene Based TE Materials
Graphene is a two-dimensional (2D) monolayer material with only one carbon atom thickness. The most promising method for transparent conductive graphene electrodes in optoelectronic devices is reportedly synthesized via chemical vapor deposition, where graphene films are deposited directly on a substrate such as Cu foil by passing a carbon source through a high-temperature vacuum chamber, and the synthesized graphene is transferred to the target substrate using a support film such as poly (methyl methacrylate).
  • 1.1K
  • 14 Feb 2023
Topic Review
Development of Thin Film Blackbody Radiation Source
In developing and calibrating cryogenic receivers in the terahertz and sub-terahertz frequency range, illumination from an ideal source (blackbody, BB) with exactly known power spectral density is required. An electrically heated blackbody radiation source comprising thin metal film on a dielectric substrate and an integrating cavity was designed, fabricated, and experimentally studied at frequencies from 75 to 500 GHz.
  • 1.1K
  • 28 Jul 2022
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