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Topic Review
Models of the Structure of Humic Substances
Natural organic matter, including humic substances (HS), comprises complex secondary structures with no defined covalent chemical bonds and stabilized by inter- and intra-molecular interactions, such as hydrogen bonding, Van der Waal’s forces, and pi-pi interactions. The latest view describes HS aggregates as a hydrogel-like structure comprised by a hydrophobic core of aromatic residues surrounded by polar and amphiphilic molecules akin a self-assembled soft material. A different view is based on the classification of this material as either mass or surface fractals. The former is intended as made by the clustering of macromolecules generating dendritic networks, while the latter have been modelled in terms of a solvent-impenetrable core surrounded by a layer of lyophilic material. 
  • 354
  • 22 Feb 2023
Topic Review
Mode-locking
Mode-locking is a technique in optics by which a laser can be made to produce pulses of light of extremely short duration, on the order of picoseconds (10−12 s) or femtoseconds (10−15 s). A laser operated in this way is sometimes referred to as a femtosecond laser, for example in modern refractive surgery. The basis of the technique is to induce a fixed-phase relationship between the longitudinal modes of the laser's resonant cavity. Constructive interference between these modes can cause the laser light to be produced as a train of pulses. The laser is then said to be 'phase-locked' or 'mode-locked'.
  • 2.5K
  • 03 Nov 2022
Topic Review
Moberly–Jourdain Incident
The Moberly–Jourdain incident (also the Ghosts of Petit Trianon or Versailles, French: les fantômes du Trianon / les fantômes de Versailles) is a claim of time travel and hauntings made by Charlotte Anne Moberly (1846–1937) and Eleanor Jourdain (1863–1924). In 1911, Moberly and Jourdain published a book entitled An Adventure under the names of "Elizabeth Morison" and "Frances Lamont". Their book describes a visit they made to the Petit Trianon, a small château in the grounds of the Palace of Versailles where they claimed to have seen the gardens as they had been in the late eighteenth century as well as ghosts, including Marie Antoinette and others. Their story caused a sensation and was subject to much ridicule.
  • 359
  • 22 Nov 2022
Biography
Mirza
Mirza Bichurin is Professor and Head of the Department of Design and Technology of Radioelectronic Equipment, Yaroslav-the Wise Novgorod State University, Russia. He has authored 6 books and more than 160 articles in international refereed journals and holds credit for 20 patents. His most famous works: 1.“Magnetoelectricity in Composites.” Eds. M. I. Bichurin and D. Viehland, Pan Stanf
  • 476
  • 29 Jan 2023
Topic Review
Mir EO-28
Soyuz TM-30 (Russian: Союз ТМ-30, Union TM-30), also known as Mir EO-28, was a Soyuz mission, the 39th and final human spaceflight to the Mir space station. The crew of the mission was sent by MirCorp, a privately funded company, to reactivate and repair the station. The crew also resupplied the station and boosted the station to an orbit with a low point (perigee) of 360 and a high point (apogee) of 378 kilometers (223 and 235 miles, respectively); the boost in the station's orbit was done by utilizing the engines of the Progress M1-1 and M1-2 spacecraft. At that time a transit between Mir and the International Space Station was already impossible - such a transfer was deemed undesired by NASA - and the orbital plane of ISS had been chosen some time before to be around 120 degrees away from that of Mir. The mission was the first privately funded mission to a space station. The mission was part of an effort by MirCorp to refurbish and privatize the aging Mir space station, which was nearing the end of its operational life. Further commercially funded missions beyond Soyuz TM-30 were originally planned to continue the restoration efforts of the then 14-year-old space station, but insufficient funding and investment ultimately led to the de-orbit of the station in early 2001.
  • 505
  • 25 Nov 2022
Topic Review
Minkowski Diagram
The Minkowski diagram, also known as a spacetime diagram, was developed in 1908 by Hermann Minkowski and provides an illustration of the properties of space and time in the special theory of relativity. It allows a qualitative understanding of the corresponding phenomena like time dilation and length contraction without mathematical equations. Minkowski diagrams are two-dimensional graphs that depict events as happening in a universe consisting of one space dimension and one time dimension. Unlike a regular distance-time graph, the distance is displayed on the horizontal axis and time on the vertical axis. Additionally, the time and space units of measurement are chosen in such a way that an object moving at the speed of light is depicted as following a 45° angle to the diagram's axes. In this way, each object, like an observer or a vehicle, traces a certain line in the diagram, which is called its world line. Also, each point in the diagram represents a certain position in space and time, and is called an event, regardless of whether anything relevant happens there and then.
  • 2.7K
  • 10 Oct 2022
Topic Review
Mining for Gluon Saturation
Quantum chromodynamics (QCD) is the theory of strong interactions of quarks and gluons collectively called partons, the basic constituents of all nuclear matter. Its non-abelian character manifests in nature in the form of two remarkable properties: color confinement and asymptotic freedom. At high energies, perturbation theory can result in the growth and dominance of very gluon densities at small-x. If left uncontrolled, this growth can result in gluons eternally growing violating a number of mathematical bounds. The resolution to this problem lies by balancing gluon emissions by recombinating gluons at high energies : phenomena of gluon saturation. High energy nuclear and particle physics experiments have spent the past decades quantifying the structure of protons and nuclei in terms of their fundamental constituents confirming predicted extraordinary behavior of matter at extreme density and pressure conditions. In the process they have also measured seemingly unexpected phenomena. We will give a state of the art review of the underlying theoretical and experimental tools and measurements pertinent to gluon saturation physics. We will argue for the need of high energy electron-proton/ion colliders such as the proposed EIC (USA) and LHeC (Europe) to consolidate our knowledge of QCD in the small x kinematic domains. 
  • 646
  • 02 Sep 2021
Topic Review
Minimal Models
In theoretical physics, a minimal model or Virasoro minimal model is a two-dimensional conformal field theory whose spectrum is built from finitely many irreducible representations of the Virasoro algebra. Minimal models have been classified and solved, and found to obey an ADE classification. The term minimal model can also refer to a rational CFT based on an algebra that is larger than the Virasoro algebra, such as a W-algebra.
  • 443
  • 07 Nov 2022
Topic Review
Minimal Model
In theoretical physics, a minimal model or Virasoro minimal model is a two-dimensional conformal field theory whose spectrum is built from finitely many irreducible representations of the Virasoro algebra. Minimal models have been classified and solved, and found to obey an ADE classification. The term minimal model can also refer to a rational CFT based on an algebra that is larger than the Virasoro algebra, such as a W-algebra.
  • 267
  • 17 Oct 2022
Topic Review
Miles-Phillips Mechanism
In physical oceanography and fluid mechanics, the Miles-Phillips mechanism describes the generation of wind waves from a flat surface by the use of two distinct mechanisms. Both mechanisms are applied on the gravity-capillary waves and have in common that waves are generated by a resonance phenomenon. The Miles mechanism is based on the hypothesis that waves arise as an instability of the sea-atmosphere system. The Phillips mechanism assumes that turbulent eddies in the atmospheric boundary layer induce pressure fluctuations at the sea surface.
  • 488
  • 13 Oct 2022
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