DC Mode Research Articles

A New Organic Laser Material Design Toward Ultra-Low Amplified Spontaneous Red Emission and Ultra-Bright Electroluminescence.

Significant efforts are dedicated to developing new classes of organic semiconductor materials to achieve electrically pumped lasing. However, further advancements are necessary to understand the relationship between the structure and property for the creation of innovative laser materials with high stability, low triplet yield, ultra-low lasing threshold, and low-efficiency roll-off at ultra-bright electroluminescence. Here, a new design principle is validated for organic semiconductor laser materials, demonstrating simultaneous enhancement in the key figures of merit of low amplified spontaneous emission thresholds (Eth), efficient electroluminescence, and low triplet yields. By applying the Einstein stimulated emission rate equation and Strickler-Berg approximation, Two red-emitting laser dimers of Cibalackrot with different linkers are constructed, leading to giant enhancement (≈250%) in oscillator strengths, and stimulated emission cross-sections. When blended in poly(9,9-dioctylfluorene-alt-benzothiadiazole), the new dimers achieve an ultra-low Eth (4.5±0.3µJcm-2) in the deep red region (λASE=655nm), among the lowest reported for deep-red emitters. Organic light-emitting diodes (OLEDs) utilizing the dimer blend exhibit low-efficiency roll-off under DC mode. Under pulse operation, the OLEDs achieve high current densities (90Am-2) and ultrahigh brightness (≈710000cdm-2). These findings highlight the dimerization design as an excellent platform to advance organic semiconductor laser materials.

Influence of luting strategies on dentin bond performance of self-adhesive resin luting cement in combination with a universal adhesive.

This study aimed to evaluate the dentin bond performance of various resin luting cement (RLC) systems combined with universal adhesives in different luting strategies. Three self-adhesive resin luting cements (SRLCs) were used with universal adhesives as primers. Twelve specimens per group were prepared to measure shear bond strength (SBS) under distinct luting strategies in etch-&-rinse and self-etch modes. Regarding luting strategies, the bonded specimens were categorized into four groups based on tooth primer application and the curing mode of the SRLC paste: (i) with light irradiation of the tooth primer (wL) + dual-cure mode (DC) of the SRLC paste, (ii) wL + self-cure mode (SC) of the SRLC paste, (iii) without light irradiation of the tooth primer (woL) + DC mode of the SRLC paste, and (iv) woL + SC mode of the SRLC paste. Specimens were also subjected to different storage conditions: 24h in water (baseline condition) and 10,000 cycles of thermal cycling. Luting strategy, storage condition, and SRLC system type significantly influenced dentin SBS values in both etching modes. Notably, certain SRLCs exhibited significantly higher dentin SBS when the primer was light-irradiated compared with no primer irradiation. Most SRLCs demonstrated higher dentin bond strength with light-irradiated primers, suggesting potential enhancement of dentin bond performance via primer light irradiation.

Exploring the Performance of Alkaline Water Electrolyzers Under Dynamic Operational Conditions

Green hydrogen, produced through water electrolysis driven by Renewable Energy Sources (RES), is a compelling solution for storing renewable energy. Directly coupling RES with water electrolyzers enhances system efficiency and cost-effectiveness. Alkaline water electrolysis, a mature and cost-effective technology, faces challenges operating under fluctuating RES conditions using AC/DC convertor , which supply rippled DC. A comprehensive understanding of electrolyzer performance in dynamic conditions is crucial for developing durable, efficient systems.In the present experimental study, we extensively explored the performance of alkaline water electrolyzers and the key factors influencing it under dynamic operational conditions. The electrolytic cell was constructed using a zero-gap configuration, comprising a NiCoOx-based anode deposited on a Ni-mesh and an Ln-doped RuOx cathode deposited on a fine mesh of Ni metal. The Zirfon Perl UTP500 membrane served as a separator between the two cell compartments [1]. A 7.0 Molar KOH electrolyte at a room temperature of approximately 30°C was employed. The cell underwent dynamic operational mode through the application of a square wave cell voltage, shown in Fig.1 (a), utilizing the NF BP4620 power supply. Square waves with different frequencies, specifically 1, 100, 1000, and 3000 Hz, were employed. Steady-state operations were conducted while applying various DC voltages, serving as a reference study. The resulting current and the actual cell voltage waveforms were monitored and recorded using a high-resolution oscilloscope (YOKOGAWA DL850E). The flow of H2 gas was measured using a film flow meter (HORIBA STEC, SF series VP-3). The apparent power, real power, and reactive power components were calculated using formulas from a previously published report [2]. Subsequently, the specific energy consumption was determined for each condition.The applied cell voltages were categorized into two groups. In the first category, the maximum cell voltage (Vmax) was set at 2.0 V, a value sufficiently high and suitable for industrial cell operation when applied in a DC mode. Within this category, the minimum cell voltage (Vmin) took various values, namely 1.8, 1.6, and 1.4 V. In the second category, the average cell voltage was maintained at a constant 2.0 V, while the amplitude of the waveform was adjusted to 0.2 and 0.4 V by modifying both Vmax and Vmin. Figure 1(b) depicts the resulting current of the voltage waveform at 100 Hz, illustrating three different Vmin values. The figure reveals that at a high Vmin of 1.8V, the current consistently maintained positive values during the voltage cycle, indicating that the double-layer capacitance remained charged throughout the operational period. However, with Vmin set at 1.6V, a relatively small capacitive current emerged, suggesting partial discharge of the double-layer capacitance. Moreover, at a lower Vmin of 1.4V, the cell voltage became insufficient to drive water electrolysis in the current cell. Consequently, a relatively large negative (capacitive) current manifested during the Vmin period, denoting a deep discharge of the double-layer capacitance.The obtained results revealed a profound influence of the charge and discharge status of the double-layer capacitance on the AWE cell's performance throughout the voltage cycles. Notably, when the double-layer capacitor remained fully charged during the voltage cycles, minimal impact of the frequency was observed on key performance parameters, including H2 flow rate that shown in figure 1 (c), specific energy consumption that shown in figure 1 (d), and power factor. However, under conditions of partial discharge within the cell voltage cycles, a noticeable correlation between the size and frequency of the voltage waveform and the AWE cell's performance emerged. Deep discharge of the double-layer capacitance led to a frequency-dependent reduction in H2 flow rate, attributed to incomplete charge/discharge cycles. Hence, the critical factor influencing the performance of the electrolytic cell during dynamic operation is the condition (charging/discharging) of the double-layer capacitance. These findings offer valuable insights into optimizing the dynamic operation of AWE cells for enhanced efficiency and performance. Acknowledgments: This research was partially supported by New Energy and Industrial Technology Development Organization (NEDO).

Characterization of the LEBT based neutron source

Neutron generation by implantation and subsequent beam interaction of 40 keV deuterons at Soreq Applied Research Accelerator Facility (SARAF) low energy beam transport (LEBT) section was measured and characterized. The generation of 2.45 MeV neutrons by a deuteron beam of several mA was verified by a neutron spectrometer. Relative neutron yields were studied as a function of beam energy and beam spot size using two types of available implantation surfaces. The buildup of neutron yield was studied at long and short time scales. Absolute neutron yield was measured via activation at several conditions. The maximum neutron yield that could be obtained at the SARAF LEBT is of the order of 107 n/s, which presents a convenient source for testing neutron instrumentation in DC or pulsed mode.

The influence of Sm[formula omitted]O[formula omitted] nanoparticles adding on some superconducting properties of Bi[formula omitted]Pb[formula omitted]Sr[formula omitted]Ca[formula omitted]Cu[formula omitted]O[formula omitted] ceramics

High-Temperature Superconductors Bi1.6Pb0.4Sr2Ca2Cu3O10+δ samples doped with Sm2O3 nanoparticles in different quantities (0.00, 0.02, 0.04 and 0.06), were synthesised. Solid state feedback technique was used to prepare the samples and then characterised. The morphology and structure of the specimens were deployed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) examination. The spectroscopy of the energy dispersive X-ray (EDX) experiment was utilised to obtain the elemental composition of the samples. Resistivity versus temperature measurement in DC mode was employed to estimate the critical transition temperature of each sample. XRD with the Rietveld refinement process revealed that Bi2223 and Bi2212 stages exist mutually in specimens with orthorhombic crystal systems. The lowest percentage of volume fraction associated with the Bi2223 phase belonged to the sample with x=0.06 nanoparticle samarium doped. It was detected that with rising samarium content the volume division of the Bi2223 phase decreases but the Bi2212 stage increases compared with the pristine specimen. SEM showed that the shrinkage of grain size occurs when the amount of nano-sized Sm was added to x=0.02 sample with lower inter-coupling among superconducting granules. This effect might be verified by SEM and TEM images. EDX exhibited some peaks related to Sm and other elements of the Bi2223 structure. These patterns confirm that all elements associated with the compounds were introduced into the Bi2223 matrix. The critical temperatures such as Tconset, TcPeak and Tczero decreased for Sm doped samples compared with the pure sample. Adding Sm2O3 nanoparticles causes rising calculated density and hole carrier concentration. These outcomes can be interpreted as the allocation of additional positive charges to the CuO2 planes. It is worth mentioning that the superb properties such as high-Tc, high Jc, strong flux pinning, and good thermal stability, for Bi2223 and high breakdown electric field, high dielectric constant, and large bandgap for Sm2O3 are the issues to motivate the author to dope Bi2223 with Sm2O3 NPs. In brief, the electrical, mechanical and structural properties of Sm2O3 NPs doped Bi2223 play the main role in the applications, which drive the investigations to emphasise the synthesis of superconducting samples.

Monolithic integrated circuit LNA 5–10 GHz

One of the features of the current stage of development of microwave electronics is the widespread use of monolithic integrated circuits. The interest of radio-electronic equipment developers in MIS is caused not only by better microwave characteristics compared to modules made using hybrid technology, but also by economic feasibility, ease of setup and reproducibility of parameters of finished products. An integral part of the transmitting and receiving paths of such systems are MMICs of low noise amplifiers. The goal of the work is to implement a matched MIC microwave low-noise amplifier with operating frequencies from 5 to 10 GHz with a noise figure of at least 1.2 dB and a gain of at least 20 dB. To develop an amplifier with operating frequencies up to 10 GHz, technology with a design standard of 0.25 microns was chosen. To meet the requirements, a two-stage circuit with automatic bias was selected. The widths of the transistors were selected taking into account the analysis of the minimum achievable noise figure and the balance between current consumption and output power. The autobias of the first stage is organized using an inductor. This solution allows not only to set the required DC mode, but also ensures input matching of the amplifier. The second stage is covered by negative feedback, which has a positive effect on the stability of the amplifier and its output matching. The amplifier supply voltage is 5 V, while resistors in the DC filter circuits set the required voltage value at the drain of each stage. Based on electrodynamic analysis, a topology was synthesized and an MIC was manufactured in the form of a gallium arsenide crystal 1.8 x 1.8 mm in size and 100 μm thick. An experimental study of manufactured LNA samples showed that in the frequency range from 5 GHz to 10 GHz the noise figure does not exceed 1.2 dB, while the minimum gain in the operating band is 21 dB. Characteristics of the amplifier has good temperature stability. The main parameters of the manufactured microcircuit are at the level of parameters of foreign analogues.

Ultra-sensitive measurement of small optical rotation angles using quantum entanglement based on a quasi-Wollaston prism beam splitter

The measurement of optical rotation is fundamental to optical atomic magnetometry. Ultra-high sensitivity has been achieved by employing a quasi-Wollaston prism as the beam splitter within a quantum entanglement state, complemented by synchronous detection. Initially, we designed a quasi-Wollaston prism and intentionally rotated the crystal axis of the exit prism element by a specific bias angle. A linearly polarized light beam, incident upon this prism, is divided into three beams, with the intensity of each beam correlated through quantum entanglement. Subsequently, we formulated the equations for optical rotation angles by synchronously detecting the intensities of these beams, distinguishing between differential and reference signals. Theoretical analysis indicates that the measurement uncertainty for optical rotation angles, when using quantum entanglement, exceeds the conventional photon shot noise limit. Moreover, we have experimentally validated the effectiveness of our method. In DC mode, the experimental results reveal that the measurement uncertainty for optical rotation angles is 4.7 × 10−9 rad, implying a sensitivity of 4.7 × 10−10 rad/Hz1/2 for each 0.01 s measurement duration. In light intensity modulation mode, the uncertainty is 48.9 × 10−9 rad, indicating a sensitivity of 4.89 × 10−9 rad/Hz1/2 per 0.01 s measurement duration. This study presents a novel approach for measuring small optical rotation angles with unprecedentedly low uncertainty and high sensitivity, potentially playing a pivotal role in advancing all-optical atomic magnetometers and magneto-optical effect research.

Determination of Self-Heating in Silicon Photomultipliers.

The main consequence of radiation damage on a silicon photomultiplier (SiPM) is a significant increase in the dark current. If the SiPM is not adequately cooled, the power dissipation causes it to heat up, which alters its performance parameters. To investigate this heating effect, a measurement cycle was developed and performed with a KETEK SiPM glued to an Al2O3 substrate and with HPK SiPMs glued to either an Al2O3 substrate or a flexible PCB. The assemblies were connected either directly to a temperature-controlled chuck on a probe station, or through layers of materials with defined thermal resistance. An LED operated in DC mode was used to illuminate the SiPM and to tune the power dissipated in a measurement cycle. The SiPM current was used to determine the steady-state temperature reached by the SiPM via a calibration curve. The increase in SiPM temperature due to self-heating is analyzed as a function of the power dissipation in the SiPM and the thermal resistance. This information can be used to adjust the operating voltage of the SiPMs, taking into account the effects of self-heating. Similarly, this approach can be applied to investigate the unknown thermal contact of packaged SiPMs.

Comparative Evaluation of Dual-Purpose Converters Suitable for Application in DC and AC Grids

This paper presents a comparative evaluation of several topological solutions to the universal power electronics interface for the dc or single-phase ac grids using the same terminals. The idea of a dual-purpose approach lies in the utilization of the same semiconductors in the dc-dc and in the dc-ac configuration, resulting in minimal redundancy. Particular focus is on the power density improvement and control. Out of the three solutions under investigation, the first is the buck-boost cell with unfolding circuit presented earlier. The second solution is a conventional voltage source inverter with an intermediate boost cell considered as one of obvious competitors. The third design is based on a phase-modular solution with buck-boost cells. The design example and experimental prototypes of the universal power electronics interface converter rated for 3.6 kVA power in the ac mode and more than 5 kW in the dc mode are presented. Our experimental results demonstrate the ability of operation in the ac or dc grids with main corresponding modes. Possible applications along with main benefits are addressed in the conclusions.

Additive manufacturing multiscale ultrahigh strength and high accuracy nanocrystalline nickel structures and components using ultrafine anode scanning through-mask electrodeposition

Through-mask electrodeposition (TM-ECD) is a widely-used technique for manufacturing mesoscale and microscale precision metal features and components in a mass-production manner. However, in most cases, the traditional TM-ECD processes are very hard to fabricate high-accuracy multiscale (macroscale, mesoscale, microscale) features simultaneously due to the inherent nonuniform distribution of the applied energy fields including electric field, mass transportation field, and temperature field during electrodeposition. Furthermore, nanocrystalline microstructures have not been realized by TM-ECD without additional nonmetallic additives or mechanical stirring. Here, a ultrafine anode scanning through-mask electrodeposition (UASTM-ECD) process operated at DC mode is developed to further trigger the formation of nanocrystalline without additives, in which a ultrafine wire-shaped inert anode embedded in a stirring paddle reciprocates over the top surfaces of the through-masks with a spacing of less than 100 μm. Experimental investigations into this unique TM-ECD were systemically carried out by examining the geometrical profile, surface morphologies, forming accuracy, grain size, and mechanical properties of the fabricated nanocrystalline structures and components. Our findings showed that the UASTM-ECD can facilitate to achieve a significantly improved thickness distribution uniformity and considerably fine nanocrystalline ultrapure microscale and mesoscale complex cross-sectional arrays components over the traditional TM-ECD processes even though the multiscale features and components are simultaneously deposited on the same substrate. These result from the unique deposition manner of the UASTM-ECD in which the metal materials are intermittently filled into the patterned photoresist cavity molds very locally and at the extremely high current densities. This versatile approach eliminates the possible contamination by additives and integration difficulty of mechanical stirring, which can be used to fabricate the multiscale ultrahigh strength and high accuracy ultrapure nanostructured-material features.

Pulse electrodeposition synthesis of Ti/PbO2-IrO2 nano-composite electrode to restrict the OER in the zinc electrowinning

Pulsed and constant direct current electrodepositions were applied to synthesize PbO2-IrO2 nano-composites on Ti substrate. By compositing PbO2 with nano-sized IrO2 particles, a suitable anode was prepared for zinc electrowinning that decreases the electrocatalytic activity for oxygen evolution reaction overpotential (OER) while increasing the electrochemical active surface area and the electrocatalytic activity for OER. To provide PbO2-IrO2 nano-composites on Ti substrate with Sb2O3 interlayer, current density, temperature, and time of anodization are optimized using the one-at-the-time method. The optimal condition for the anode involves a DC time of 1 h, incorporating 2 g L-1 of IrO2 nanoparticles, maintaining a current density of 50 mA cm− 2 for the DC mode, and setting the pulse off-time (toff) to 770 ms. Based on the electrochemical evaluations in a simulated zinc electrowinning electrolyte, the effect of IrO2 nanoparticles on the catalytic activity of Ti/β-PbO2 anode for OER was determined. Anodic polarization curves showed that the OER overpotential of PbO2-IrO2 micro-composite and PbO2-IrO2 nano-composites at a current density of 10 mA cm-2 decreased to 0.471 V, respectively, compared to 0.711 V for pure PbO2. The Nyquist plots in the OER zone confirm that the PbO2-IrO2 nano-composite anode exhibits the lowest Rct 2.79 Ω compared to 6.0 Ω and 9.46 Ω for PbO2-IrO2 micro-composite and pure PbO2, which can be attributed to the presence of electro-catalytic IrO2 nanoparticles.

Overall performance of Ni-Co-WC nanocomposite coatings prepared by ultrasonic vibration-assisted scanning jet electrodeposition

To obtain a high-performance Ni-Co-WC nanocomposite coating on 45# steel, this work proposed a novel ultrasonic vibration-assisted scanning jet electrodeposition and used the range of WC nanoparticles concentration (3-12 g/L) in the electrolyte as the key variable in this study. Through harmonic response analysis, a 31 kHz frequency ultrasonic transducer was selected as the vibration source to achieve better vibration effects. The type of current mode that we employed was DC mode. The influence of ultrasonic vibration and the concentration of WC nanoparticles in the electrolyte on the surface morphology, micro-texture, microhardness, adhesion, and corrosion resistance of the nanocomposite coating were investigated by using SEM, XRD, Vickers microhardness tester, scratch tester and electrochemical workstation respectively. Compared to conventional scanning jet electrodeposition, the results indicated that the ultrasonic vibration improved the surface morphology, mechanical properties, and corrosion resistance of the coating, with the hardness increased by 15.9 % and the adhesion strength increased by 76.1 % as well as the corrosion current density decreased by 13.0 %. When the WC concentration in the electrolyte was 6 g/L, the Ni-Co-WC nanocomposite coating prepared by ultrasonic vibration-assisted composite scanning jet electrodeposition exhibited the best surface quality and properties. The microhardness of the coating was the highest at 590 HV, the adhesion strength was the largest at 33.4 N and the corrosion current density was as low as 4.104 μA·cm−2. Compared with the WC concentration of 3 g/L, when the WC concentration was 6 g/L, the hardness increased by 7.8 %, the adhesion strength increased by 41.5 % whereas the corrosion current density decreased by 30.6 %. In addition, molecular dynamics simulation was employed to calculate the effect of WC content in the coating on the binding energy between the coating and the substrate. The simulation results confirmed that the adhesive strength between the composite coating and substrate was directly proportional to the WC content in the composite coating. Therefore, this research is of great significance for the protection of offshore platform support structure materials and the improvement of their service life.

Smart electro-magneto-viscoelastomer minimum energy structures with particle-reinforcements: Theoretical equilibrium and nonlinear dynamics of actuated configurations

Soft transduction technology is rapidly adopting soft active elastomer-based minimum energy structures because of their distinctive programmable shape-morphing characteristics. For effective device design, an understanding of the nonlinear dynamic behavior is crucial as they often experience time-dependent motion while operating. Moreover, there has been an increasing scientific interest in enhancing the actuation performance of soft active elastomers by imparting particle reinforcements. This article provides a theoretical framework for investigating the nonlinear dynamics of smart composite elastomer-based minimum energy structures (SCEMES) with the provision of non-aligned electric and magnetic fields, leading to an actively programmable pre-stretch paradigm. Unlike conventional actuators, the proposed SCEMES is made up of a polymer that has electro-magnetic properties and is filled with appropriate fillers with specific volume fractions. An electromagneto-viscoelastic model is developed here to predict actuator behavior and investigate the effects of particle reinforcement on equilibrium and actuated configurations. Besides strengthening the polymer, particle reinforcement is observed to enhance the equilibrium angle achieved by the structure with enhanced functionality. The proposed nonlinear dynamic model is extended to investigate a number of critically influential parameters, including shear modulus ratio of fiber to matrix, frame bending stiffness, membrane pre-stretching, and electro-magnetic loading with time-dependent DC and AC modes of actuation. The results reveal that the combined electro-magnetic actuation enhances the actuation range significantly. The attained tip angle of the actuator increases appreciably when the magnetic and electric fields are applied mutually perpendicular to each other, indicating that the direction of applied magnetic field governs the attained actuated configuration. Further, particle reinforcement enrichments result in a depletion in oscillation amplitudes and an increase in excitation frequencies under the AC actuation mode. The efficient semi-analytical framework presented here would be crucial in developing new actuators, smart devices and soft robots for a variety of advanced engineering and medical applications.

Stimulated-source-independent persistent luminescence phosphor Sr2Ta2O7:Tb3+, Tm3+ for multi-mode anti-counterfeiting applications

The multi-mode luminescent anti-counterfeiting materials Sr2Ta2O7:Tb3+, Tm3+ were prepared, which possessed DC, UC, PSL, and PersL modes.

Investigation of the Al-Mo-B(CN) Coatings Deposited Using Magnetron Sputtering of Al-Mo-B4C Target Produced by Detonation Spray Coating

In this work, a metal–ceramic composite target for magnetron sputtering was manufactured by a robotic complex for detonation spraying of coatings equipped with a multi-chamber detonation accelerator. The powder composition (30Mo-30Al-40B4C) was sprayed onto the copper plate base of the composite target cathode. The obtained cathode target with Al-Mo-B4C coating (thickness 280–300 μm) was used to deposit the Al-Mo-B(CN) coating (DC mode) on flat specimens of AISI 316 steel and silicon using equipment for magnetron sputtering UNICOAT 200. The Al-Mo-B4C coating has a lamella-type structure with inclusions of boron carbide particles. The structure and morphology of the coatings were studied using methods of optical analysis, scanning electron microscopy, atomic force microscopy, X-ray analysis, and X-ray photoelectron spectroscopy. Mechanical and tribological properties of the Al-Mo-B(CN) thin coatings were studied using a nanoindenter, a scratch tester, and a tribometer under a fluid-free friction regime at room temperature. The Al-Mo-B(CN) coating (thickness ~1 μm) exhibited a dense homogeneous fine-grained design without columnar elements and had an amorphous structure. The formation of the MoB2 and AlN phase with an admixture of oxygen in the form of aluminum oxide, molybdenum oxide, and boron oxide was determined using XPS analysis. The Al-Mo-B(CN) coating possessed a hardness of 13 GPa, an elasticity modulus of 114 GPa, an elastic recovery of 45%, a friction coefficient of 0.8 against a steel 100 Cr6 ball, and an adhesion strength of 11 N.

Memristors Constructed by CsPbIBr2 Inorganic Halide Perovskite for Artificial Synapse and Logic Operation

Neuromorphic devices are one of the promising electronic devices that are implementing artificial neural networks and substituting for traditional semiconductor devices in recent years. Inorganic halide perovskite (IMHP) is considered as an advantageous material to constitute neuromorphic components. Herein, the CsPbIBr2 memristor displays superior resistive‐switching properties under various temperature and storage periods. In addition, synaptic plasticity, including paired pulse facilitation and spiking timing‐dependent plasticity, is observed for CsPbIBr2 device, whose resistance manipulation is also established in both DC and pulse modes. Moreover, the decimal operation function of numbers by applying pulse stimulation to the device to regulate the device conductance is realized. This work demonstrates the feasibility of IMHP in neuromorphic devices, accelerating the application of neuromorphic computing.

Effect of current pulse pattern on Ce3+-doped (Gd,Lu)3Al5O12 ceramics fabricated by spark plasma sintering

To investigate the effect of the current pulse pattern on the PL emission characteristics, Ce3+:(Gd,Lu)3Al5O12 ceramics were fabricated by the SPS process on separators (BN powder and C paper) and current pulse patterns (DC and BC modes). In the DC mode of the SPS process, the reduction process caused by the carbon atmosphere occurred relatively more actively than in the BC mode. During annealing, the oxidation process also excessively occurred compared to the BC mode, and consequently, the Ce3+ fraction in the DC mode was significantly reduced. In the present work, the Ce3+ fraction served as the most dominant factor affecting the PL emission characteristics than the microstructure and dopant distribution. As a result, despite the discrepancy in the relative density of about 1.2%, the PL emission characteristics were improved because the Ce3+ fraction of only 0.4% was high.

Trisodium citrate as a potential and eco-friendly corrosion inhibitor of copper in potable water

In this work, the mixture of trisodium cittrate and Zn2+ was used as binary (hetero type) inhibitor for corrosion inhibition of copper metal in potable water. The binary inhibitor system (Zn2+ and trisodium citrate) was used to form hydrophobic surfaces on copper submerged in potable water. Water contact angle (WCA) was found to be 155°4° when the inhibitor was present, whereas it was 84°2° when there was no inhibitor. These observations suggested the development of superhydrophobic layer on the surface of copper in drinkable water. Electrochemical impedance spectroscopy (EIS – AC mode), and potentiodynamic polarization (DC mode) experiments conveyed that the copper surface could be protected by utilizing the mixture of trisodium citrate and Zn2+ in potable water. The morphological studies including SEM (coupled with EDX), AFM, and WCA were evidenced the formulation of a hetero-type inhibitor for the corrosion inhibition of copper in potable water. In this study, the decline in the double-layer capacitance and the rise in the charge transfer resistance were due to the adsorption of inhibitor confirming the development of protective layer, which EIS, SEM, EDX, AFM, and WCA studies also supported. Thus, there was a synergism observed between TSC and Zn2+, and the formulation consisting of TSC and Zn2+ provided 83% of inhibition efficiency (IEp). So, it was suggested that the approach reported in this study could be a simple method for obtaining the superhydrophobic copper surface.

Recent Advances in Cerium Oxide-Based Memristors for Neuromorphic Computing.

This review article attempts to provide a comprehensive review of the recent progress in cerium oxide (CeO2)-based resistive random-access memories (RRAMs). CeO2 is considered the most promising candidate because of its multiple oxidation states (Ce3+ and Ce4+), remarkable resistive-switching (RS) uniformity in DC mode, gradual resistance transition, cycling endurance, long data-retention period, and utilization of the RS mechanism as a dielectric layer, thereby exhibiting potential for neuromorphic computing. In this context, a detailed study of the filamentary mechanisms and their types is required. Accordingly, extensive studies on unipolar, bipolar, and threshold memristive behaviors are reviewed in this work. Furthermore, electrode-based (both symmetric and asymmetric) engineering is focused for the memristor's structures such as single-layer, bilayer (as an oxygen barrier layer), and doped switching-layer-based memristors have been proved to be unique CeO2-based synaptic devices. Hence, neuromorphic applications comprising spike-based learning processes, potentiation and depression characteristics, potentiation motion and synaptic weight decay process, short-term plasticity, and long-term plasticity are intensively studied. More recently, because learning based on Pavlov's dog experiment has been adopted as an advanced synoptic study, it is one of the primary topics of this review. Finally, CeO2-based memristors are considered promising compared to previously reported memristors for advanced synaptic study in the future, particularly by utilizing high-dielectric-constant oxide memristors.

Electromagnetic effects and accurate wall-temperature measurement method under directly electric heating mode

By directly imposed electrical energy on metal materials with low voltage but high current to generate Joule heat is an effective energy conversion method. The corresponding temperature will quickly reach the predetermined value. It is also an effective way to achieve homogeneous heating or local non-uniform heating in the heterogeneous conductive elements, thus directly electric heating is widely used in scientific experiments and industrial practices. However, direct electrical heating method may effect by electromagnetic effect (skin effect or proximity effect) and interfere on the sensor, results in inconsistent temperature distribution or inaccurate temperature, even under the condition with power frequency (f = 50 Hz or 60 Hz). In the present paper, a comparative experimental investigation on temperature distribution of multiple parallel blocks at steady and transient process under DC and AC heating mode have been measured by infrared camera and thermocouples. It is found that the temperature measured by AC heating is always lower than that measured by DC heating under the same apparent power applied effected by electromagnetic effect. Three different sensor installations used for temperature measurement is also discussed and found an effective installation method. The electric field and temperature field in parallel blocks is further analyzed by electromagnetic-thermal coupling multiphysics solver after model verification. Moreover, another experiment discovered that the imposed external DC potential will generate a non-linear interference to the measured temperature, the temperature sensor with a good insulation can get more accurate result. These result can provide a technical guidance for direct electrical heating scientific researches and industrial application.