Study on Switching Characteristics and Associated Degradation Mechanism of Contact Material Under Capacitive Load

Cyclic dinucleotides (CDNs) have emerged as the central molecules that aid bacteria to adapt and thrive in changing environmental conditions. Therefore, tight regulation of intracellular CDN concentration by counteracting the action of dinucleotide cyclases and phosphodiesterases (PDEs) is critical. Here, we demonstrate that a putative stand-alone EAL domain PDE from Vibrio cholerae (VcEAL) is capable to degrade both the second messenger c-di-GMP and hybrid 3′3′-cyclic GMP–AMP (cGAMP). To unveil their degradation mechanism, we have determined high-resolution crystal structures of VcEAL with Ca2+, c-di-GMP-Ca2+, 5′-pGpG-Ca2+ and cGAMP-Ca2+, the latter provides the first structural basis of cGAMP hydrolysis. Structural studies reveal a typical triosephosphate isomerase barrel-fold with substrate c-di-GMP/cGAMP bound in an extended conformation. Highly conserved residues specifically bind the guanine base of c-di-GMP/cGAMP in the G2 site while the semi-conserved nature of residues at the G1 site could act as a specificity determinant. Two metal ions, co-ordinated with six stubbornly conserved residues and two non-bridging scissile phosphate oxygens of c-di-GMP/cGAMP, activate a water molecule for an in-line attack on the phosphodiester bond, supporting two-metal ion-based catalytic mechanism. PDE activity and biofilm assays of several prudently designed mutants collectively demonstrate that VcEAL active site is charge and size optimized. Intriguingly, in VcEAL-5′-pGpG-Ca2+ structure, β5–α5 loop adopts a novel conformation that along with conserved E131 creates a new metal-binding site. This novel conformation along with several subtle changes in the active site designate VcEAL-5′-pGpG-Ca2+ structure quite different from other 5′-pGpG bound structures reported earlier.

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Stochastic Models of Particle Trajectories in Turbulent Atmosphere Flows by Using the LANGEVIN Equations

Proceedings ◽

10.3390/proceedings2020063032 ◽

2020 ◽

Vol 1 (1) ◽

Author(s):

Youssra El Qasemy ◽

Abdelfatah Achahbar ◽

Abdellatif Khamlichi

Keyword(s):

Wind Speed ◽

Wind Turbine ◽

Classical Method ◽

Degradation Mechanism ◽

Transformation Process ◽

Langevin Equations ◽

Turbulence Data ◽

Power Curves ◽

And Diffusion ◽

Fluctuating Wind

The stochastic behavior of wind speed is a particular characteristic of wind energy production, which affects the degradation mechanism of the turbine, resulting in stochastic charging on the wind turbine. A model stochastic is used in this study to evaluate the efficiency of wind turbine power of whatever degree given fluctuating wind turbulence data. This model is based on the Langevin equations, which characterize, by two coefficients, drift and diffusion functions. These coefficients describe the behavior of the transformation process from the input wind speed to the output data that need to be determined. For this present work, the computation of drift and diffusion functions has been carried out by using the stochastic model to assess the output variables in terms of the torque and power curves as a function of time, and it is compared by the classical method. The results show that the model stochastic can define the efficiency of wind turbine generation more precisely.

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Deposition of Bi2O3 Thin Films and Their Resistive Switching Characteristics

Journal of Inorganic Materials ◽

10.3724/sp.j.1077.2012.00323 ◽

2012 ◽

Vol 27 (3) ◽

pp. 323-326

Author(s):

Zhen-Guo JI ◽

Jun-Jie WANG ◽

Qi-Nan MAO ◽

Jun-Hua XI

Keyword(s):

Thin Films ◽

Resistive Switching ◽

Switching Characteristics

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Synthesis, Characterization and Thermal Degradation of Some New 3,5-dimethyl Pyrazole Derivatives

Revista de Chimie ◽

10.37358/rc.17.2.5444 ◽

2017 ◽

Vol 68 (2) ◽

pp. 317-322

Author(s):

Anca Mihaela Mocanu ◽

Constantin Luca ◽

Alina Costina Luca

Keyword(s):

Thermal Degradation ◽

Degradation Mechanism ◽

New Products ◽

Analysis Data ◽

Biological Properties ◽

Elemental Analysis Data ◽

Ftir Analysis ◽

Spectral Measurements ◽

Chemical Structures ◽

And Storage

The purpose of this research is to synthetize, characterize and thermal degradation of new heterolytic derivates with potential biological properties. The derivates synthesis was done by obtaining new molecules with pyralozone structure which combine two pharmacophore entities: the amidosulfonyl-R1,R2 phenoxyacetil with the 3,5-dimethyl pyrazole which can have potential biological properties. The synthesis stages of the new products are presented as well as the elemental analysis data and IR, 1H-NMR spectral measurements made for elucidating the chemical structures and thermostability study which makes evident the temperature range proper for their use and storage. The obtained results were indicative of a good correlation of the structure with the thermal stability as estimated by means of the initial degradation temperatures as well as with the degradation mechanism by means of the TG-FTIR analysis.

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Effect of Top Electrode Materials on Switching Characteristics and Endurance Properties of Zinc Oxide Based RRAM Device

Journal of Nano- and Electronic Physics ◽

10.21272/jnep.12(1).01007 ◽

2020 ◽

Vol 12 (1) ◽

pp. 01007-1-01007-6

Author(s):

Chandra Prakash Gupta ◽

◽

Praveen K. Jain ◽

Umesh Chand ◽

Shashi Kant Sharma ◽

...

Keyword(s):

Zinc Oxide ◽

Electrode Materials ◽

Switching Characteristics

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Titania Based Nano-ionic Memristive Crossbar Arrays: Fabrication and Resistive Switching Characteristics

Nanoscience &Nanotechnology-Asia ◽

10.2174/2210681208666180628122146 ◽

2019 ◽

Vol 9 (4) ◽

pp. 486-493 ◽

Cited By ~ 1

Author(s):

S. Sahoo ◽

P. Manoravi ◽

S.R.S. Prabaharan

Keyword(s):

Resistive Switching ◽

Bottom Electrode ◽

Rf Sputtering ◽

Hysteresis Curve ◽

Bipolar Switching ◽

Post Annealing ◽

Endurance Tests ◽

Bilayer Device ◽

Switching Characteristics ◽

Pinched Hysteresis

Introduction: Intrinsic resistive switching properties of Pt/TiO2-x/TiO2/Pt crossbar memory array has been examined using the crossbar (4×4) arrays fabricated by using DC/RF sputtering under specific conditions at room temperature. Materials and Methods: The growth of filament is envisaged from bottom electrode (BE) towards the top electrode (TE) by forming conducting nano-filaments across TiO2/TiO2-x bilayer stack. Non-linear pinched hysteresis curve (a signature of memristor) is evident from I-V plot measured using Pt/TiO2-x /TiO2/Pt bilayer device (a single cell amongst the 4×4 array is used). It is found that the observed I-V profile shows two distinguishable regions of switching symmetrically in both SET and RESET cycle. Distinguishable potential profiles are evident from I-V curve; in which region-1 relates to the electroformation prior to switching and region-2 shows the switching to ON state (LRS). It is observed that upon reversing the polarity, bipolar switching (set and reset) is evident from the facile symmetric pinched hysteresis profile. Obtaining such a facile switching is attributed to the desired composition of Titania layers i.e. the rutile TiO2 (stoichiometric) as the first layer obtained via controlled post annealing (650oC/1h) process onto which TiO2-x (anatase) is formed (350oC/1h). Results: These controlled processes adapted during the fabrication step help manipulate the desired potential barrier between metal (Pt) and TiO2 interface. Interestingly, this controlled process variation is found to be crucial for measuring the switching characteristics expected in Titania based memristor. In order to ensure the formation of rutile and anatase phases, XPS, XRD and HRSEM analyses have been carried out. Conclusion: Finally, the reliability of bilayer memristive structure is investigated by monitoring the retention (104 s) and endurance tests which ensured the reproducibility over 10,000 cycles.

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Recent Achievements in Development of TiO2-Based Composite Photocatalytic Materials for Solar Driven Water Purification and Water Splitting

Materials ◽

10.3390/ma13061338 ◽

2020 ◽

Vol 13 (6) ◽

pp. 1338 ◽

Cited By ~ 7

Author(s):

Klara Perović ◽

Francis M. dela Rosa ◽

Marin Kovačić ◽

Hrvoje Kušić ◽

Urška Lavrenčič Štangar ◽

...

Keyword(s):

Water Treatment ◽

Transition Metal ◽

Photocatalytic Degradation ◽

Water Splitting ◽

Water Purification ◽

Degradation Mechanism ◽

Living Environment ◽

Solar Irradiation ◽

Metal Chalcogenides ◽

Photocatalytic Water Splitting

Clean water and the increased use of renewable energy are considered to be two of the main goals in the effort to achieve a sustainable living environment. The fulfillment of these goals may include the use of solar-driven photocatalytic processes that are found to be quite effective in water purification, as well as hydrogen generation. H2 production by water splitting and photocatalytic degradation of organic pollutants in water both rely on the formation of electron/hole (e−/h+) pairs at a semiconducting material upon its excitation by light with sufficient photon energy. Most of the photocatalytic studies involve the use of TiO2 and well-suited model compounds, either as sacrificial agents or pollutants. However, the wider application of this technology requires the harvesting of a broader spectrum of solar irradiation and the suppression of the recombination of photogenerated charge carriers. These limitations can be overcome by the use of different strategies, among which the focus is put on the creation of heterojunctions with another narrow bandgap semiconductor, which can provide high response in the visible light region. In this review paper, we report the most recent advances in the application of TiO2 based heterojunction (semiconductor-semiconductor) composites for photocatalytic water treatment and water splitting. This review article is subdivided into two major parts, namely Photocatalytic water treatment and Photocatalytic water splitting, to give a thorough examination of all achieved progress. The first part provides an overview on photocatalytic degradation mechanism principles, followed by the most recent applications for photocatalytic degradation and mineralization of contaminants of emerging concern (CEC), such as pharmaceuticals and pesticides with a critical insight into removal mechanism, while the second part focuses on fabrication of TiO2-based heterojunctions with carbon-based materials, transition metal oxides, transition metal chalcogenides, and multiple composites that were made of three or more semiconductor materials for photocatalytic water splitting.

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Design and Switching Characteristics of Flip-Chip GaN Half-Bridge Modules Integrated with Drivers

Applied Sciences ◽

10.3390/app11157057 ◽

2021 ◽

Vol 11 (15) ◽

pp. 7057

Author(s):

Lin Wang ◽

Zhe Cheng ◽

Zhi-Guo Yu ◽

De-Feng Lin ◽

Zhe Liu ◽

...

Keyword(s):

Flip Chip ◽

High Electron Mobility Transistors ◽

Wire Bonding ◽

High Electron ◽

Parasitic Inductance ◽

Switching Performance ◽

Turn On ◽

Electron Mobility Transistors ◽

Chip Technology ◽

Switching Characteristics

Half-bridge modules with integrated GaN high electron mobility transistors (HEMTs) and driver dies were designed and fabricated in this research. Our design uses flip-chip technology for fabrication, instead of more generally applied wire bonding, to reduce parasitic inductance in both the driver-gate and drain-source loops. Modules were prepared using both methods and the double-pulse test was applied to evaluate and compare their switching characteristics. The gate voltage (Vgs) waveform of the flip-chip module showed no overshoot during the turn-on period, and a small oscillation during the turn-off period. The probabilities of gate damage and false turn-on were greatly reduced. The inductance in the drain-source loop of the module was measured to be 3.4 nH. The rise and fall times of the drain voltage (Vds) were 12.9 and 5.8 ns, respectively, with an overshoot of only 4.8 V during the turn-off period under Vdc = 100 V. These results indicate that the use of flip-chip technology along with the integration of GaN HEMTs with driver dies can effectively reduce the parasitic inductance and improve the switching performance of GaN half-bridge modules compared to wire bonding.

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Multi-level characteristics of TiOx transparent non-volatile resistive switching device by embedding SiO2 nanoparticles

Scientific Reports ◽

10.1038/s41598-021-89315-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sera Kwon ◽

Min-Jung Kim ◽

Kwun-Bum Chung

Keyword(s):

Resistive Switching ◽

High Performance ◽

Sio2 Nanoparticles ◽

Visible Range ◽

Resistive State ◽

Switching Device ◽

Structural Density ◽

Multi Level ◽

Switching Characteristics ◽

Switching Devices

AbstractTiOx-based resistive switching devices have recently attracted attention as a promising candidate for next-generation non-volatile memory devices. A number of studies have attempted to increase the structural density of resistive switching devices. The fabrication of a multi-level switching device is a feasible method for increasing the density of the memory cell. Herein, we attempt to obtain a non-volatile multi-level switching memory device that is highly transparent by embedding SiO2 nanoparticles (NPs) into the TiOx matrix (TiOx@SiO2 NPs). The fully transparent resistive switching device is fabricated with an ITO/TiOx@SiO2 NPs/ITO structure on glass substrate, and it shows transmittance over 95% in the visible range. The TiOx@SiO2 NPs device shows outstanding switching characteristics, such as a high on/off ratio, long retention time, good endurance, and distinguishable multi-level switching. To understand multi-level switching characteristics by adjusting the set voltages, we analyze the switching mechanism in each resistive state. This method represents a promising approach for high-performance non-volatile multi-level memory applications.

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