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Topic Review
Isotopes of Osmium
Osmium (76Os) has seven naturally occurring isotopes, five of which are stable: 187Os, 188Os, 189Os, 190Os, and (most abundant) 192Os. The other natural isotopes, 184Os, and 186Os, have extremely long half-life (1.12×1013 years and 2×1015 years, respectively) and for practical purposes can be considered to be stable as well. 187Os is the daughter of 187Re (half-life 4.56×1010 years) and is most often measured in an 187Os/188Os ratio. This ratio, as well as the 187Re/188Os ratio, have been used extensively in dating terrestrial as well as meteoric rocks. It has also been used to measure the intensity of continental weathering over geologic time and to fix minimum ages for stabilization of the mantle roots of continental cratons. However, the most notable application of Os in dating has been in conjunction with iridium, to analyze the layer of shocked quartz along the Cretaceous–Paleogene boundary that marks the extinction of the dinosaurs 66 million years ago. There are also 30 artificial radioisotopes, the longest-lived of which is 194Os with a half-life of six years; all others have half-lives under 94 days. There are also nine known nuclear isomers, the longest-lived of which is 191mOs with a half-life of 13.10 hours. All isotopes and nuclear isomers of osmium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.
  • 512
  • 27 Oct 2022
Biography
Edwin C. Kemble
Edwin Crawford Kemble (January 28, 1889 in Delaware, Ohio – March 12, 1984) was an American physicist who made contributions to the theory of quantum mechanics and molecular structure and spectroscopy. During World War II, he was a consultant to the Navy on acoustic detection of submarines and to the Army on Operation Alsos.[1] Kemble began college in 1906 at Ohio Wesleyan University, but h
  • 512
  • 08 Dec 2022
Topic Review
Simple Models of Pulmonary Artifacts
Nowadays, the diagnostic value of the artefactual information provided by lung ultrasound images is widely recognized by physicians. In particular, the existence of a correlation between the visual characteristics of the vertical artifacts, which arise from the pleura line, and the genesis (pneumogenic or cardiogenic) of a pulmonary disorder is commonly accepted. However, the link between these visual characteristics and the causes which determine them is still unclear. In order to derive further information from the visual inspection of the vertical artifacts the mechanisms which control the artifact formation must be identified. The link between the visual characteristics of the vertical artifacts (the observed effect) and the distribution of the aerated spaces at the pleural level (the cause) must be addressed. Plausible mechanisms should be illustrated through experimental results and through the theoretical analysis of simple models.
  • 511
  • 27 Oct 2021
Topic Review
Mean Field Particle Methods
Mean field particle methods are a broad class of interacting type Monte Carlo algorithms for simulating from a sequence of probability distributions satisfying a nonlinear evolution equation. These flows of probability measures can always be interpreted as the distributions of the random states of a Markov process whose transition probabilities depends on the distributions of the current random states. A natural way to simulate these sophisticated nonlinear Markov processes is to sample a large number of copies of the process, replacing in the evolution equation the unknown distributions of the random states by the sampled empirical measures. In contrast with traditional Monte Carlo and Markov chain Monte Carlo methods these mean field particle techniques rely on sequential interacting samples. The terminology mean field reflects the fact that each of the samples (a.k.a. particles, individuals, walkers, agents, creatures, or phenotypes) interacts with the empirical measures of the process. When the size of the system tends to infinity, these random empirical measures converge to the deterministic distribution of the random states of the nonlinear Markov chain, so that the statistical interaction between particles vanishes. In other words, starting with a chaotic configuration based on independent copies of initial state of the nonlinear Markov chain model, the chaos propagates at any time horizon as the size the system tends to infinity; that is, finite blocks of particles reduces to independent copies of the nonlinear Markov process. This result is called the propagation of chaos property. The terminology "propagation of chaos" originated with the work of Mark Kac in 1976 on a colliding mean field kinetic gas model
  • 511
  • 26 Oct 2022
Topic Review
Dense Superconducting Hydrides
To date, about twenty hydrides experiments have been reported to exhibit high-Tc superconductivity and their Tc agree well with the predicted values. However, there are still some controversies existing between the predictions and experiments.
  • 510
  • 20 Dec 2021
Topic Review
Treatment of Chrysanthemum Synthetic Seeds by SDBD Plasma
Implementation of the surface dielectric barrier discharge (SDBD) plasma treatment before sowing represents a promising strategy for future investigations and sustainable use of cold plasma in synseed biotechnology. Plasma-treated chrysanthemum synseeds showed a better survival rate and overall plantlet growth under greenhouse conditions in comparison to untreated synseeds.
  • 509
  • 12 Apr 2022
Biography
Uschi Steigenberger
Ursula "Uschi" Steigenberger (25 April 1951 — 12 December 2018) OBE FInstP was a German condensed matter physicist and director of the ISIS neutron source. She was one of the founders of the Institute of Physics Juno Award. Steigenberger was born in Augsburg. She studied physics at the University of Würzburg, where she remained for her graduate studies. She earned a PhD in condensed matter
  • 508
  • 01 Dec 2022
Biography
Herman Carr
Herman Y. Carr (November 28, 1924 – April 9, 2008), who published as H. Y. Carr, was an American physicist and pioneer of magnetic resonance imaging. Dr. Carr was born in Alliance, Ohio where he was an Alliance High School graduate in January 1943; he later was inducted into their Hall of Fame. He served in the Army as a Sergeant in the 12th Weather Squadron Air Corps during World War II in It
  • 506
  • 08 Dec 2022
Topic Review
High-Performance Silicon Optoelectronic Devices Based on Graphene
Graphene—a two-dimensional allotrope of carbon in a single-layer honeycomb lattice nanostructure—has several distinctive optoelectronic properties that are highly desirable in advanced optical communication systems. Meanwhile, silicon photonics is a promising solution for the next-generation integrated photonics, owing to its low cost, low propagation loss and compatibility with CMOS fabrication processes.
  • 506
  • 19 Jan 2022
Biography
Mikhail Mikhaylovich Rusinov
Mikhail Mikhaylovich Rusinov (Russian: Михаи́л Миха́йлович Руси́нов, 11 February 1909 – 29 September 2004) was an outstanding Russian scientist, specialising in optics. Mikhail Rusinov co-founded the USSR Science School of Computational Optics and discovered several optical phenomena, including aberration vignetting (1938), projection centre distortion (1957), and exi
  • 506
  • 27 Dec 2022
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