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Applications of engineered nanoparticles in biomedicine
Published in Binoy K. Saikia, Advances in Applied Chemistry and Industrial Catalysis, 2022
Wenjin Huang, Junqiang Lyu, Xuanhua Zhang, Yixiang Zhang
This nanoscale substance appeals to scientists so much because these particles are in the middle ground between the macro system and its micro counterpart, which provides them unique characteristics that can be applied in the field of biomedicine, including quantum tunneling effect, quantum size effect, and larger proportion of the surface area. The Quantum tunneling effect demonstrates the tunneling of microscopic electrons through barriers. Quantum size effect describes two phenomena: electron energy level changes from quasi-continue to discrete energy level near the fermi level of metal, or the band gap widens when the discontinuous exists between the highest orbital energy level and the lowest one. Also, by scaling law, along with the decrease of the size of nanoparticles, the number of atoms on the surface increases dramatically, and there are more dangling bonds. Therefore, they are chemically active as well. On account of these nanoparticles-only characteristics, nanoparticles can have extraordinary stiffness and display special phenomena such as the blue-shift effect.
Nanoelectronics: Basic Concepts, Approaches, and Applications
Published in Rakesh K. Sindhu, Mansi Chitkara, Inderjeet Singh Sandhu, Nanotechnology, 2021
Balwinder Kaur, Radhika Marwaha, Subhash Chand, Balraj Saini
Quantum tunneling refers to the quantum mechanical phenomenon where a particle tunnels through a barrier that it classically could not surmount. Classical mechanics could not explain this phenomenon. The difference arises because classical mechanics treated matter as solely particles, whereas quantum mechanics emphasizes upon wave-like character of material particles, i.e., dual character of matter. Heisenberg’s uncertainty principle imposes a limit on the simultaneous measurement of position and momentum of particles accurately and forms the basis. It implies that there are no regions of zero probability; hence, the probability of the given particle to exist on the opposite side of the barrier is nonzero, which leads to its tunneling on another side of the barrier.
Signals, Noise, and Thresholds
Published in Ben Greenebaum, Frank Barnes, Bioengineering and Biophysical Aspects of Electromagnetic Fields, 2018
There is, however, another way to cross an activation barrier. A particle that does not have enough kinetic energy to overcome a potential barrier can nevertheless get across the barrier through the process of “quantum tunneling.”104 Tunneling explains many natural phenomena and has technological applications. The Scanning Tunneling Microscope, for instance, has a sharp conducting tip that scans a surface and records the current of electrons that tunnel through the vacuum between the tip and the surface. Such microscopes allow for the characterization of a surface on a subnanometer scale.105
KNOWM memristors in a bridge synapse delay-based reservoir computing system for detection of epileptic seizures
Published in International Journal of Parallel, Emergent and Distributed Systems, 2022
Dawid Przyczyna, Grzegorz Hess, Konrad Szaciłowski
To address the computational problems of the modern age, scientists are working to improve existing hardware and software technologies, as well as develop unconventional and/or hybrid approaches known as heteroic computing [12]. The growth of the first approach is commonly known to be subjected to Moore’s law, whereas the second approach attempts to overcome its limitations through embedded multifunctionality and interaction with the environment [13]. Moore’s law states that computational capabilities of conventional transistor technologies will double every few years. However, there is a lower limit to miniaturisation due to (i) the granularity of matter and (ii) the effects of quantum tunnelling of electrons through the gate of the transistor and (iii) heat management problems, which are the main reasons for looking for other computational technologies [14–19]. Second major issue is the so-called Von Neuman Bottleneck. It is a problem that limits the computing abilities of classic computers resulting from the separation of memory functions and processing that require communication between these components, which in turn limits the speed of the computing process. One of the novel technologies that aims to resolve some of modern computing problems is the application of memristors (and other memristive elements) and memristive circuits [20–24].
Tailoring geometric phases of two-dimensional functional materials under light: a brief review
Published in International Journal of Smart and Nano Materials, 2020
Besides BTO which has a rotation of polarization axis, two individual groups focused on SrTiO3 (STO) which has a more complicated phase diagram. The low temperature STO is also ferroelectric. However, as the temperature is lowered sufficiently, the quantum tunneling effect (zero temperature energy) becomes significantly, and the system shows paraelectric character. This is termed as quantum paraelectricity [29]. In 2019, two back-to-back papers published in Science reported their experimental observations of a ‘hidden’ phase at low temperature, when the STO is illuminated under terahertz laser [30,31]. They use terahertz laser, which could excite the phonon (ionic system) of STO, and the quantum paraelectric STO undergoes a phase transformation and becomes ferroelectric without an inversion symmetry. The second harmonic generation measurements clearly demonstrate such phase change. Since this phase cannot be observed in conventional p-T phase diagram, it is a hidden phase that only appears under finite alternating electric field E with selective frequency and intensity. Unfortunately, the exact ferroelectric atomic structure is still unknown (Figure 6).
Tunneling rules for electronic transport in 1-D systems
Published in Molecular Physics, 2021
C.A.B. da Silva, K.R. Nisioka, M. Moura-Moreira, R.F. Macedo, J. Del Nero
In the simulation, the bond length is not forced in polyyne or cumulene. As a result, we obtained the polyyne situation (–C≡C–) [34], which has the diameter (width) of 1C atom (≈1.34 Å) and presents 16C atoms (4C left lead – 4C molecule – dn – 4C molecule – 4C right lead) for the molecular device. The electronic transport occurs by tunnel effect or quantum tunneling. The calculations start from a distance (dn) of 4 Å between the polyynes varying each system in 0.1 Å up to a distance (dn) of 2.1 Å.