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Monochromatic X-ray has a single energy level in contrast to white X-rays used in conventional radiation therapy. Irradiation of high Z elements such as gadolinium, gold and silver with a monochromatic X-ray can result in photoelectric effects that includes the release of the Auger electrons that have strong cell killing effect. To apply this principle to cancer therapy, various nanoparticles loaded with high Z elements have been developed that enabled high Z elements to be delivered to tumor. The recent addition is gadolinium-loaded mesoporous silica nanoparticle (Gd-MSN). Tumor spheroids have been used as a convenient tumor model to demonstrate that monochromatic X-rays with energy level at or higher than the K-edge energy of gadolinium can destruct tumor mass that has Gd-MSN distributed throughout tumor spheroids.
22 Jul 2020
Computational Chemistry Methods
The main objective of computational chemistry is to solve chemical problems by simulating chemical systems (molecular, biological, materials) in order to provide reliable, accurate and comprehensive information at an atomic level. To this end, there are two main methodological families: those based on quantum chemical methods and those based on molecular mechanics. The former are methods in which the electrons are explicitly accounted for, while in the latter their presence is hidden in the force field.
17 Jun 2021
Inelastic Neutron Scattering
Inelastic neutron scattering (INS) is a spectroscopy based on the energy analysis of neutrons after they have been scattered by a sample. A detected energy transfer can be related to a physical interaction of the corresponding atoms with their environment. An energy transfer of several meVs typically arises from vibrations of atoms. Thus, INS provides an amplitude-of-motion and neutron incoherent cross section weighted phonon density of states. Given the much higher incoherent scattering cross section of hydrogen relative to that of all other elements, INS is particular sensitive to hydrogen based vibrations. The method is widely used in condensed matter physics and solid state chemistry, because the vibrational properties of matter define various physical properties such as the heat capacity. If used as a fingerprint method, INS can be used to characterize chemical bonds both in the bulk as well as on the surface.
30 Oct 2020
An Unmanned System (US) or Vehicle (UV) can be defined as an “electro-mechanical system, with no human operator aboard, that is able to exert its power to perform designed missions”
17 Mar 2021
Angle-Resolved Photoemission Spectroscopy (ARPES)
Angle-resolved photoemission spectroscopy (ARPES) is a vital technique in which spectra are collected from both the energy and momentum of photoemitted electrons and is indispensable for investigating the electronic band structure of solids.
08 Dec 2020
Nature-inspired optimization algorithms
Over previous decades, many nature-inspired optimization algorithms (NIOAs) have been proposed and applied due to their importance and significance. Some survey studies have also been made to investigate NIOAs and their variants and applications. However, these comparative studies mainly focus on one single NIOA, and there lacks a comprehensive comparative and contrastive study of the existing NIOAs.
11 Nov 2021
Lithium-Ion Battery Fire Suppression
Lithium-ion Batteries (LiBs) hazards, techniques for mitigating risks, the suppression of LiB fires and identification of shortcomings for future improvement were thoroughly reviewed. Water is identified as an efficient cooling and suppressing agent and water mist is considered the most promising technique to extinguish LiBs fire.
29 Apr 2021
Closed Timelike Curves
Closed timelike curves (CTCs) are space-time trajectories that return to their starting point without violating the laws of special relativity. A traveler along a CTC could journey into the future but arrive in its past, creating a possible violation of the principle of causality. Such CTCs occur in Gödel’s rotating universe and many other general relativistic solutions of classical Einstein’s field equations. The chronological protection conjecture suggests that Nature forbids this kind of situation.
27 Jan 2021
We briefly review applications of surface-plasmon polariton modes, related to the design and fabrication of electro–optical circuits.
30 Oct 2020
Optical Phase Shifters
Optical phase shifters have the functionality to control the phase of light by a change in the effective refractive index. In a Si photonics platform, it is an essential part composing optical modulators as well as switches in Si photonics. The realization of a silicon optical phase shifter marked a cornerstone for the development of silicon photonics, and it is expected that optical interconnects based on the technology relax the explosive datacom growth in data centers. High-performance silicon optical modulators and switches, integrated into a chip, play a very important role in optical transceivers, encoding electrical signals onto the light at high speed and routing the optical signals, respectively. The development of the devices is continuously required to meet the ever-increasing data traffic at higher performance and lower cost.
08 Jun 2021
Featured Entry Collections
Encyclopedia of Social Sciences
Encyclopedia of ZEMCH Research and Development
Encyclopedia of Engineering
Encyclopedia of Piezoelectrics
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