Encyclopedia
Scholarly Community
Encyclopedia
Entry
Video
Image
Journal
Book
News
About
Entry
Entry
Video
Image
Log in/Sign up
Submit
Entry
Video
Image
Subject:
All Disciplines
Arts & Humanities
Biology & Life Sciences
Business & Economics
Chemistry & Materials Science
Computer Science & Mathematics
Engineering
Environmental & Earth Sciences
Medicine & Pharmacology
Physical Sciences
Public Health & Healthcare
Social Sciences
Sort:
Hottest
Latest
Alphabetical (A-Z)
Alphabetical (Z-A)
Type:
All
Topic Review
Biography
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.
350
22 Feb 2023
Topic Review
Sensor Applications of Forward Brillouin Scattering
In-fiber opto-mechanics based on forward Brillouin scattering enables sensing the surrounding of the optical fiber. Optical fiber transverse acoustic resonances are sensitive to both the inner properties of the optical fiber and the external medium. A particularly efficient pump and probe technique—assisted by a fiber grating—can be exploited for the development of point sensors of only a few centimeters in length. When measuring the acoustic resonances, this technique provides the narrowest reported linewidths and a signal-to-noise ratio better than 40 dB. The longitudinal and transverse acoustic velocities—normalized with the fiber radius—can be determined with a relative error lower than 10−4, exploiting the derivation of accurate asymptotic expressions for the resonant frequencies.
366
17 Feb 2023
Topic Review
Liquid Crystal-Tuned Planar Optics in Terahertz Range
Terahertz waves of higher frequencies compared to microwave and radio frequency have shown great potential in radar detection and high-speed wireless communication. To spatially control the wavefront of terahertz beams, various novel components, such as terahertz filters, polarization converters and lenses, have been investigated. Metamaterials and metasurfaces have become the most promising technique for the free manipulation of terahertz waves. Metadevices integrated with liquid crystals have been widely used in active terahertz devices.
463
17 Feb 2023
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).
525
14 Feb 2023
Topic Review
Classification of Continuous-Variable Quantum Key Distribution Protocols
Quantum communications, in general, and quantum key distribution (QKD) as one of the internal directions, in particular, are some of the most actively developing areas of quantum technologies. QKD allows one to send a secure key between several legitimate users connected by so-called quantum and classical channels. Theoretically, the security of QKD is based on the principles of quantum mechanics, which guarantees security against any unforeseen technological developments, for example, in the field of quantum computing.
986
14 Feb 2023
Topic Review
Probe for Single-Molecule Fluorescence Microscopy
Probe choice in single-molecule microscopy requires deeper evaluations than those adopted for less sensitive fluorescence microscopy studies. Fluorophore characteristics can alter or hide subtle phenomena observable at the single-molecule level, wasting the potential of the sophisticated instrumentation and algorithms developed for this kind of advanced applications. The three typical groups of fluorophores are fluorescent proteins, organic dyes and quantum dots; here their advantages, drawbacks and use in single-molecule microscopy are discussed. Some requirements are common to all applications, such as high brightness and photostability, specific and efficient labeling, controlled stoichiometry, no perturbation on the system. Other requirements depend on the specific type of single-molecule technique; some of them are here described with their specific requirements for probe choice.
788
13 Feb 2023
Topic Review
Two-Dimensional Materials in Nonlinear Optical Devices
All-optical signal processing based on nonlinear optical devices is promising for ultrafast information processing in optical communication systems. Recent advances in two-dimensional (2D) layered materials with unique structures and distinctive properties have opened up new avenues for nonlinear optics and the fabrication of related devices with high performance.
374
13 Feb 2023
Topic Review
Multi-Color Light-Emitting Diodes
Multi-color light-emitting diodes (LEDs) with various advantages of color tunability, self-luminescence, wide viewing angles, high color contrast, low power consumption, and flexibility provide a wide range of applications including full-color display, augmented reality/virtual reality technology, and wearable healthcare systems.
745
13 Feb 2023
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”.
507
10 Feb 2023
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.
482
08 Feb 2023
Page
of
118
Featured Entry Collections
>>
Featured Books
>>
Encyclopedia of Social Sciences
Chief Editor:
Michael McAleer
Encyclopedia of COVID-19
Chief Editor:
Stephen Bustin
Encyclopedia of Fungi
Chief Editor:
Luis V. Lopez-Llorca
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Chief Editor:
Sandro Serpa
Entry
Video
Image
Journal
Book
News
About
Log in/Sign up
New Entry
New Video
New Images
About
Terms and Conditions
Privacy Policy
Advisory Board
Contact
Partner
Video Production Service
Feedback
Top
Feedback
×
Help Center
Browse our user manual, common Q&A, author guidelines, etc.
Rate your experience
Let us know your experience and what we could improve.
Report an error
Is something wrong? Please let us know!
Other feedback
Other feedback you would like to report.
×
Did you find what you were looking for?
Love
Like
Neutral
Dislike
Hate
0
/500
Email
Do you agree to share your valuable feedback publicly on
Encyclopedia
’s homepage?
Yes, I agree. Encyclopedia can post it.
No, I do not agree. I would not like to post my testimonial.
Webpage
Upload a screenshot
(Max file size 2MB)
Submit
Back
Close
×