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Topic Review
Applications of Liquid Crystals-Based Sensors
Liquid crystals are a class of chemical substances that exist in intermediate states between crystalline solids and liquids. They thus share the anisotropic properties of crystalline solids as well as fluid properties of isotropic liquids. 
  • 3.1K
  • 23 Mar 2022
Topic Review
Applications of Nanotechnology
The applications of nanotechnology, commonly incorporate industrial, medicinal, and energy uses. These include more durable construction materials, therapeutic drug delivery, and higher density hydrogen fuel cells that are environmentally friendly. Bein that nanoparticles and nanodevices are highly versatile through modification of their physiochemical properties, they have found uses in nanoscale electronics, cancer treatments, vaccines, hydrogen fuel cells, and nanographene batteries. Nanotechnology's use of smaller sized materials allows for adjustment of molecules and substances at the nanoscale level, which can further enhance the mechanical properties of materials or grant access to less physically accessible areas of the body.
  • 884
  • 29 Sep 2022
Topic Review
Artificial Gravity in Fiction
Artificial gravity is a common theme in fiction, particularly science fiction.
  • 4.0K
  • 21 Oct 2022
Topic Review
Astronomy
Astronomy (from grc ἀστρονομία (Script error: No such module "Ancient Greek".) 'science that studies the laws of the stars') is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Babylonians, Greeks, Indians, Egyptians, Chinese, Maya, and many ancient indigenous peoples of the Americas. In the past, astronomy included disciplines as diverse as astrometry, celestial navigation, observational astronomy, and the making of calendars. Nowadays, professional astronomy is often said to be the same as astrophysics. Professional astronomy is split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects. This data is then analyzed using basic principles of physics. Theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. These two fields complement each other. Theoretical astronomy seeks to explain observational results and observations are used to confirm theoretical results. Astronomy is one of the few sciences in which amateurs play an active role. This is especially true for the discovery and observation of transient events. Amateur astronomers have helped with many important discoveries, such as finding new comets.
  • 1.1K
  • 05 Dec 2022
Topic Review
Astronomy & Astrophysics
Astronomy & Astrophysics is a peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics. The journal is run by a Board of Directors representing 27 sponsoring countries plus a representative of the European Southern Observatory. The main editors of A&A are the editor-in-chief,  Thierry Forveille (fr); the Letters editor-in-chief, João Alves; and the managing editor David Elbaz. The journal is published by EDP Sciences in 12 issues per year. With an impact factor of 5.802 (2020), A&A is one of the most important academic journals in its field. Several sections of the journal are available in Open Access, and the latest issue is also available for free online reading on the journal website.
  • 377
  • 09 Nov 2022
Topic Review
Astrophysics
Astrophysics is the branch of astronomy that employs the principles of physics and chemistry "to ascertain the nature of the astronomical objects, rather than their positions or motions in space". Among the objects studied are the Sun, other stars, galaxies, extrasolar planets, the interstellar medium and the cosmic microwave background. Emissions from these objects are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, astrophysicists apply concepts and methods from many disciplines of physics, including classical mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics. In practice, modern astronomical research often involves a substantial amount of work in the realms of theoretical and observational physics. Some areas of study for astrophysicists include their attempts to determine the properties of dark matter, dark energy, black holes, and other celestial bodies; whether or not time travel is possible, wormholes can form, or the multiverse exists; and the origin and ultimate fate of the universe. Topics also studied by theoretical astrophysicists include Solar System formation and evolution; stellar dynamics and evolution; galaxy formation and evolution; magnetohydrodynamics; large-scale structure of matter in the universe; origin of cosmic rays; general relativity, special relativity, quantum and physical cosmology, including string cosmology and astroparticle physics.
  • 949
  • 15 Nov 2022
Topic Review
Asymmetric Conductivity in Heavy-Fermion Metals
We consider the time reversal T and particle-antiparticle C symmetries that, being most fundamental, can be violated at microscopic level by a weak interaction. The notable example here is from condensed matter, where strongly correlated Fermi systems like HF metals and high-Tc superconductors (or HF compounds) exhibit C and T symmetries violation due to the so-called non-Fermi liquid (NFL) behavior rather than to microscopic inter-particle interaction. When a HF compound is near the topological fermion condensation quantum phase transition (FCQPT), it exhibits the NFL properties, so that the C symmetry breaks down, making the differential tunneling conductivity to be an asymmetric function of the bias voltage V. This asymmetry does not take place in normal metals, where Landau Fermi liquid (LFL) theory holds. Under the application of magnetic field, a HF compound transits to the LFL state, and σ(V) becomes symmetric function of V. These findings are in good agreement with experimental observations. We suggest that the same topological FCQPT defines the baryon asymmetry in the Universe. Thus, the most fundamental features of the nature are defined by its topological and symmetry properties.
  • 1.9K
  • 29 Apr 2021
Topic Review
Augmented Reality in K-12 Education
Augmented Reality (AR) could provide key benefits in education and create a richer user experience by increasing the motivation and engagement of the students. Initially, AR was used as a science-oriented tool, but after its acceptance by students and teachers, it evolved into a modern pedagogical tool that was adopted into the classroom to enhance the educational process. In summary, AR-based technology has become a popular topic in educational fields in the last decade as well as in educational research [26]. Taking into consideration various modern educational disciplines, technologies such as AR must be included in the learning environment in science education; otherwise, the absence of them could possibly negatively affect productivity and learning achievements [27]. However, the educational values of AR in the domain of physical science are not exclusively based on the use of AR technologies themselves. These educational values are more likely connected to how AR is designed, implemented and integrated into formal and informal learning settings [28].
  • 711
  • 11 Aug 2022
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.
  • 562
  • 27 Jun 2023
Topic Review
Barrier Grid Animation and Stereography
Barrier-grid animation, also known as a kinegram, and "picket fence" animation, which was originated in the late 1890s and then re-popularized by Rufus Butler Seder's trademarked "Scanimation(r)" books in the early 2,000s, is an animation effect created by moving a striped transparent overlay across an interlaced image. The barrier-grid technique and its history overlap with parallax stereography (also known as "Relièphographie") for 3D autostereograms. The technique has also been used for color-changing pictures, but to a much lesser extent. The development of barrier-grid technologies can also be regarded as a step towards lenticular printing, although the technique has remained after the invention of lenticular technologies as a relatively cheap and simple way to produce animated images in print.
  • 737
  • 18 Nov 2022
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