scholarly journals EXPERIMENTAL OBSERVATION OF CHIRAL MAGNETIC BOBBERS AND NEW CONCEPT FOR MAGNETIC SOLID-STATE MEMORY

2019 ◽  
Vol 47 (1) ◽  
pp. 109-110
Author(s):  
F.N. Rybakov ◽  
A.B. Borisov
Keyword(s):  
Solid State ◽  
Binary Data ◽  
Electron Holography ◽  
Spin Orbit Coupling ◽  
Practical Applications ◽  
Wide Range ◽  
New Type ◽  
Magnetic Solid ◽  
Magnetic Skyrmions ◽  
Strong Spin

Chiral magnetic skyrmions are nanoscale vortex-like spin textures that form in the presence of an applied magnetic field in ferromagnets that support the DzyaloshinskiiMoriya interaction (DMI) because of strong spin-orbit coupling and broken inversion symmetry of the crystal. Recently, a new type of localized particle-like object – the chiral bobber (ChB) – was predicted theoretically (Rybakov et al., 2015) in such materials. Here, we report the direct observation of ChBs (Zheng et al., 2018) in thin films of B20-type FeGe by means of quantitative off-axis electron holography. Furthermore, we show that ChBs are able to coexist with skyrmions over a wide range of parameters, which suggests their possible practical applications in novel magnetic solid-state memory devices, in which a stream of binary data bits can be encoded by a sequence of skyrmions and bobbers. Work was performed within the state task of FANO Russia (subject “Quantum,” No. g.r. 01201463332) (АААА-А18-118020190095-4)).

A New Detector System For The HB5 Stem Instrument

1985 ◽  
Vol 43 ◽  
pp. 134-135
Author(s):  
J.M. Cowley
Keyword(s):  
Dark Field ◽  
Detector System ◽  
Electron Holography ◽  
Small Specimen ◽  
Bright Field ◽  
Multiple Images ◽  
Practical Applications ◽  
Wide Range ◽  
Diffraction Patterns ◽  
Operational Modes

The HB5 STEM instrument at ASU has been modified previously to include an efficient two-dimensional detector incorporating an optical analyser device and also a digital system for the recording of multiple images. The detector system was built to explore a wide range of possibilities including in-line electron holography, the observation and recording of diffraction patterns from very small specimen regions (having diameters as small as 3Å) and the formation of both bright field and dark field images by detection of various portions of the diffraction pattern. Experience in the use of this system has shown that sane of its capabilities are unique and valuable. For other purposes it appears that, while the principles of the operational modes may be verified, the practical applications are limited by the details of the initial design.

New type of sludge density meter using microwaves for application in sewage treatment plants

1996 ◽  
Vol 33 (1) ◽  
pp. 53-60
Author(s):  
Seiji Yamaguchi
Keyword(s):  
Phase Difference ◽  
Sewage Treatment ◽  
Field Tests ◽  
Measuring Method ◽  
Microwave Measurement ◽  
Sewage Treatment Plants ◽  
Practical Applications ◽  
Treatment Processes ◽  
Wide Range ◽  
New Type

Sludge density is an important index for the control of sewage and sludge treatment processes. A new measuring method for sludge density, the microwave phase difference method, has been tested with a good correlation between density and phase difference. Comparison tests with conventional ultrasonic density meters have shown characteristics that are superior to the flow-through type and equivalent to the defoaming type. We developed a sludge density meter that uses this method and made long-term field tests on the sludge pipelines in sewage treatment plants. Results demonstrated a good correlation with the values that were obtained by manual analysis, with excellent linearity from low density of less than 1% to high density of about 30%. This new microwave measurement method is less affected by soil build-up and air bubbles, is able to measure a wide range of densities from low to high, and is capable of continuous measurement. It is a highly reliable measuring method for practical applications.

Savings operations with random commencement and conclusion

2019 ◽  
Vol 20 (5) ◽  
pp. 520-541
Author(s):  
María del Carmen Valls Martínez ◽  
Salvador Cruz Rambaud ◽  
Emilio Abad Segura
Keyword(s):  
Pension Plans ◽  
Point Of View ◽  
Added Value ◽  
Content Type ◽  
Practical Applications ◽  
Proposed Model ◽  
Wide Range ◽  
New Type ◽  
Private Savings ◽  
Public Pension Plans

Purpose The progressive aging of the population is suggesting that public pension plans should be increasingly supplemented by private savings schemes. Accordingly, this supposes the appearance of a wide range of innovative savings products to meet the varying needs of savers and financial institutions. In practice, most contracted savings operations are nonrandom, that is to say, all amounts involved in the transaction are sure as well as their respective maturities. Consequently, the purpose of this paper is to propose a savings operation which includes the randomness derived from the contingencies which suppose the eventual but unpredictable death of the saver and a person designated by him to receive the final agreed amount. Design/methodology/approach The methodology used in this paper is financial mathematics where the risk has been introduced as an element which defines the main characteristics of this novel saving operation. Findings The proposed model extends the range of savings products by describing an actual innovation with new practical applications with respect to the traditional models of saving. In this paper, the authors have proposed a new type of saving based on the contingency derived from the life expectancy of the saver, by raising an operation in which the commencement and conclusion of the savings period are random. These savings operations represent, undoubtedly, a novelty from a financial point of view. Originality/value The main added value of this paper is that these contingencies affect the periodic deposits in each period from the first to the last maturities of installments. Moreover, the different parameters of such random transactions are defined.

scholarly journals New Type of Spectral Nonlinear Resonance Enhances Identification of Weak Signals

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Rongming Lin ◽  
Teng Yong Ng ◽  
Zheng Fan
Keyword(s):  
Nonlinear Resonance ◽  
Signal Enhancement ◽  
Weak Signal ◽  
Weak Signals ◽  
Practical Applications ◽  
Effective Implementation ◽  
Wide Range ◽  
New Type ◽  
Processing Techniques ◽  
Signal Processing Techniques

Abstract Some nonlinear systems possess innate capabilities of enhancing weak signal transmissions through a unique process called Stochastic Resonance (SR). However, existing SR mechanism suffers limited signal enhancement from inappropriate entraining signals. Here we propose a new and effective implementation, resulting in a new type of spectral resonance similar to SR but capable of achieving orders of magnitude higher signal enhancement than previously reported. By employing entraining frequency in the range of the weak signal, strong spectral resonances can be induced to facilitate nonlinear modulations and intermodulations, thereby strengthening the weak signal. The underlying physical mechanism governing the behavior of spectral resonances is examined, revealing the inherent advantages of the proposed spectral resonances over the existing implementation of SR. Wide range of parameters have been found for the optimal enhancement of any given weak signal and an analytical method is established to estimate these required parameters. A reliable algorithm is also developed for the identifications of weak signals using signal processing techniques. The present work can significantly improve existing SR performances and can have profound practical applications where SR is currently employed for its inherent technological advantages.

Insights into Potent Therapeutical Antileukemic Agent L-glutaminase Enzyme Under Solid-state Fermentation: A Review

2020 ◽  
Vol 21 (3) ◽  
pp. 211-220 ◽  
Author(s):  
Chandrasai Potla Durthi ◽  
Madhuri Pola ◽  
Satish Babu Rajulapati ◽  
Anand Kishore Kola
Keyword(s):  
Solid State ◽  
Solid State Fermentation ◽  
Food Industry ◽  
Energy Requirement ◽  
Production Studies ◽  
Wide Range ◽  
Hybridoma Technology ◽  
Bacteria And Fungi ◽  
The Stability ◽  
Glutaminase Activity

Aim & objective: To review the applications and production studies of reported antileukemic drug L-glutaminase under Solid-state Fermentation (SSF). Overview: An amidohydrolase that gained economic importance because of its wide range of applications in the pharmaceutical industry, as well as the food industry, is L-glutaminase. The medical applications utilized it as an anti-tumor agent as well as an antiretroviral agent. L-glutaminase is employed in the food industry as an acrylamide degradation agent, as a flavor enhancer and for the synthesis of theanine. Another application includes its use in hybridoma technology as a biosensing agent. Because of its diverse applications, scientists are now focusing on enhancing the production and optimization of L-glutaminase from various sources by both Solid-state Fermentation (SSF) and submerged fermentation studies. Of both types of fermentation processes, SSF has gained importance because of its minimal cost and energy requirement. L-glutaminase can be produced by SSF from both bacteria and fungi. Single-factor studies, as well as multi-level optimization studies, were employed to enhance L-glutaminase production. It was concluded that L-glutaminase activity achieved by SSF was 1690 U/g using wheat bran and Bengal gram husk by applying feed-forward artificial neural network and genetic algorithm. The highest L-glutaminase activity achieved under SSF was 3300 U/gds from Bacillus sp., by mixture design. Purification and kinetics studies were also reported to find the molecular weight as well as the stability of L-glutaminase. Conclusion: The current review is focused on the production of L-glutaminase by SSF from both bacteria and fungi. It was concluded from reported literature that optimization studies enhanced L-glutaminase production. Researchers have also confirmed antileukemic and anti-tumor properties of the purified L-glutaminase on various cell lines.

scholarly journals Observation of chiral surface excitons in a topological insulator Bi2Se3

2019 ◽  
Vol 116 (10) ◽  
pp. 4006-4011 ◽  
Author(s):  
H.-H. Kung ◽  
A. P. Goyal ◽  
D. L. Maslov ◽  
X. Wang ◽  
A. Lee ◽  
...  
Keyword(s):  
Polarized Light ◽  
Orbit Coupling ◽  
Experimental Investigations ◽  
Composite Particles ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Excitation Energies ◽  
Circularly Polarized Light ◽  
Pl Emission ◽  
Strong Spin

The protected electron states at the boundaries or on the surfaces of topological insulators (TIs) have been the subject of intense theoretical and experimental investigations. Such states are enforced by very strong spin–orbit interaction in solids composed of heavy elements. Here, we study the composite particles—chiral excitons—formed by the Coulomb attraction between electrons and holes residing on the surface of an archetypical 3D TI,Bi2Se3. Photoluminescence (PL) emission arising due to recombination of excitons in conventional semiconductors is usually unpolarized because of scattering by phonons and other degrees of freedom during exciton thermalization. On the contrary, we observe almost perfectly polarization-preserving PL emission from chiral excitons. We demonstrate that the chiral excitons can be optically oriented with circularly polarized light in a broad range of excitation energies, even when the latter deviate from the (apparent) optical band gap by hundreds of millielectronvolts, and that the orientation remains preserved even at room temperature. Based on the dependences of the PL spectra on the energy and polarization of incident photons, we propose that chiral excitons are made from massive holes and massless (Dirac) electrons, both with chiral spin textures enforced by strong spin–orbit coupling. A theoretical model based on this proposal describes quantitatively the experimental observations. The optical orientation of composite particles, the chiral excitons, emerges as a general result of strong spin–orbit coupling in a 2D electron system. Our findings can potentially expand applications of TIs in photonics and optoelectronics.

scholarly journals Ring-Forming Polymerization toward Perfluorocyclobutyl and Ortho-Diynylarene-Derived Materials: From Synthesis to Practical Applications

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1486
Author(s):  
Eugene B. Caldona ◽  
Ernesto I. Borrego ◽  
Ketki E. Shelar ◽  
Karl M. Mukeba ◽  
Dennis W. Smith
Keyword(s):  
Chemical Resistance ◽  
Structural Features ◽  
Review Article ◽  
Aryl Ether ◽  
Aromatic Rings ◽  
Practical Applications ◽  
Repeat Units ◽  
Wide Range ◽  
Synthetic Routes ◽  
The Cost

Many desirable characteristics of polymers arise from the method of polymerization and structural features of their repeat units, which typically are responsible for the polymer’s performance at the cost of processability. While linear alternatives are popular, polymers composed of cyclic repeat units across their backbones have generally been shown to exhibit higher optical transparency, lower water absorption, and higher glass transition temperatures. These specifically include polymers built with either substituted alicyclic structures or aromatic rings, or both. In this review article, we highlight two useful ring-forming polymer groups, perfluorocyclobutyl (PFCB) aryl ether polymers and ortho-diynylarene- (ODA) based thermosets, both demonstrating outstanding thermal stability, chemical resistance, mechanical integrity, and improved processability. Different synthetic routes (with emphasis on ring-forming polymerization) and properties for these polymers are discussed, followed by their relevant applications in a wide range of aspects.

scholarly journals Sensing of Nickel(II) Ions by Immobilizing Ligands and Using Different SPEs

2021 ◽  
Vol 6 (1) ◽  
pp. 2
Author(s):  
Liliana Anchidin-Norocel ◽  
Sonia Amariei ◽  
Gheorghe Gutt
Keyword(s):  
Bismuth Oxide ◽  
Human Population ◽  
Raw Materials ◽  
Sensor Technology ◽  
Cyclic Voltammogram ◽  
Accurate Analysis ◽  
Nickel Allergy ◽  
Nickel Ions ◽  
Practical Applications ◽  
Wide Range

The aim of this paper is the development of a sensor for the quantification of nickel ions in food raw materials and foods. It is believed that about 15% of the human population suffers from nickel allergy. In addition to digestive manifestations, food intolerance to nickel may also have systemic manifestations, such as diffuse dermatitis, diffuse itching, fever, rhinitis, headache, altered general condition. Therefore, it is necessary to control this content of nickel ions for the health of the human population by developing a new method that offers the advantages of a fast, not expensive, in situ, and accurate analysis. For this purpose, bismuth oxide-screen-printed electrodes (SPEs) and graphene-modified SPEs were used with a very small amount of dimethylglyoxime and amino acid L-histidine that were deposited. A potentiostat that displays the response in the form of a cyclic voltammogram was used to study the electrochemical properties of nickel standard solution with different concentrations. The results were compared and the most sensitive sensor proved to be bismuth oxide-SPEs with dimethylglyoxime (Bi2O3/C-dmgH2) with a linear response over a wide range (0.1–10 ppm) of nickel concentrations. Furthermore, the sensor shows excellent selectivity in the presence of common interfering species. The Bi2O3/C-dmgH2 sensor showed good viability for nickel analysis in food samples (cocoa, spinach, cabbage, and red wine) and demonstrated significant advancement in sensor technology for practical applications.

scholarly journals Quantum materials with strong spin-orbit coupling: challenges and opportunities for materials chemists

2021 ◽  
Author(s):  
Alexander J. Browne ◽  
Aleksandra Krajewska ◽  
Alexandra Gibbs
Keyword(s):  
Transition Metals ◽  
Quantum Effect ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Challenges And Opportunities ◽  
Quantum Materials ◽  
Magnetic States ◽  
Strong Spin

Spin-orbit coupling is a quantum effect that can give rise to exotic electronic and magnetic states in the compounds of the 4d and 5d transition metals. Exploratory synthesis, chemical tuning...

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