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Topic Review
Resonance
Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillating force is applied at a resonant frequency of a dynamic system, the system will oscillate at a higher amplitude than when the same force is applied at other, non-resonant frequencies. Frequencies at which the response amplitude is a relative maximum are also known as resonant frequencies or resonance frequencies of the system. Small periodic forces that are near a resonant frequency of the system have the ability to produce large amplitude oscillations in the system due to the storage of vibrational energy. Resonance phenomena occur with all types of vibrations or waves: there is mechanical resonance, Orbital resonance, acoustic resonance, electromagnetic resonance, nuclear magnetic resonance (NMR), electron spin resonance (ESR) and resonance of quantum wave functions. Resonant systems can be used to generate vibrations of a specific frequency (e.g., musical instruments), or pick out specific frequencies from a complex vibration containing many frequencies (e.g., filters). The term resonance (from Latin resonantia, 'echo', from resonare, 'resound') originated from the field of acoustics, particularly the sympathetic resonance observed in musical instruments, e.g., when one string starts to vibrate and produce sound after a different one is struck.
  • 1.1K
  • 27 Oct 2022
Topic Review
Continuous-Wave THz Imaging
Terahertz (THz) spectroscopy and imaging technology have seen significant developments in the fields of biology, medical diagnosis, food safety, and nondestructive testing. Label-free diagnosis of malignant tumours has been obtained and also achieved significant development in THz biomedical imaging.
  • 1.1K
  • 07 Jan 2021
Biography
Mazlan Othman
Professor Emerita Dato' Seri Dr Mazlan binti Othman (born 11 December 1951) is a Malaysian astrophysicist whose work has pioneered Malaysia's participation in space exploration. She was her country's first astrophysicist, and helped to create a curriculum in astrophysics at the national university, as well as to build public awareness and understanding of astronomy and space issues. She was appo
  • 1.1K
  • 18 Nov 2022
Topic Review
Fractional Schrödinger Equation
The fractional Schrödinger equation is a fundamental equation of fractional quantum mechanics. It was discovered by Nick Laskin (1999) as a result of extending the Feynman path integral, from the Brownian-like to Lévy-like quantum mechanical paths. The term fractional Schrödinger equation was coined by Nick Laskin.
  • 1.1K
  • 24 Oct 2022
Topic Review
Acoustic Emission Spectroscopy
Acoustic emission (AE) spectroscopy has become the method of choice in many fieldsbecause it is highly sensitive. For example, the AE system constructed by the Vallen company, Germany, has a sampling rate that can reach up to 10 MHz, an arrival time resolution of 100 ns, and an energy resolution of 1.8 × 10−18V2s (i.e., in the attojoule regime, aJ) referred to sensor signal at 34 dB preamplifier gain.
  • 1.1K
  • 28 Oct 2021
Topic Review
Supersonic Flow Control
In high-speed fluid dynamics, base pressure controls find many engineering applications, such as in the automobile and defense industries. Several studies have been reported on flow control with sudden expansion duct. 
  • 1.1K
  • 02 Dec 2021
Biography
Yakov Borisovich Zel'dovich
Yakov Borisovich Zel'dovich ForMemRS[1] (Belarusian: Я́каў Бары́савіч Зяльдо́віч, Russian: Я́ков Бори́сович Зельдо́вич; 8 March 1914 – 2 December 1987), also known as YaB,[2] was a Soviet physicist of Belarusian Jewish ethnicity, who is known for his prolific contributions in cosmology and the physics of thermonuclear and hydrodynamical phenome
  • 1.1K
  • 22 Nov 2022
Topic Review
Photoelectrochemical Reduction of CO2
Photoelectrochemical reduction of CO2 is a chemical process whereby carbon dioxide is reduced to carbon monoxide or hydrocarbons by the energy of incident light. This process needs to be catalyzed either homogeneously or heterogeneously in order to proceed, and current research is aimed at developing these catalysts, most of which are semiconducting materials. Semiconducting catalysts provide favourable electron transfer kinetics. The feasibility of this chemical reaction was first theorised by Giacomo Luigi Ciamician, an Italian photochemist. Already in 1912 he stated that "By  using  suitable catalyzers,  it  should  be  possible  to  transform  the mixture  of  water  and  carbon dioxide into oxygen and methane, or to cause other endo-energetic processes." Motivation for research in this area is strong due to the current attention to atmospheric carbon dioxide as the reduction of carbon dioxide would be one route for removal and sequestration. Furthermore, the reduced species may prove to be a valuable feedstock for other processes. If the incident light utilized is solar in nature then this process also potentially represents energy routes which combine renewable energy with CO2 reduction.
  • 1.1K
  • 02 Nov 2022
Topic Review
Near-Infrared Graphene/Silicon Photodetectors
In recent years, graphene has attracted much interest due to its unique properties of flexibility, strong light-matter interaction, high carrier mobility and broadband absorption. In addition, graphene can be deposited on many substrates including silicon with which is able to form Schottky junctions, opening the path to the realization of near-infrared photodetectors based on the internal photoemission effect where graphene plays the role of the metal.
  • 1.1K
  • 29 Oct 2020
Topic Review
(469219) 2016 HO3
(469219) 2016 HO3 is a micro-asteroid, fast rotator and near-Earth object of the Apollo group, approximately 41 meters in diameter. It is currently the smallest, closest, and most stable (known) quasi-satellite of Earth. The asteroid was discovered by Pan-STARRS at Haleakala Observatory on 27 April 2016.
  • 1.1K
  • 03 Nov 2022
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