Anode Voltage Research Articles

Development of a single-ended magnetic alloy loaded cavity in the Japan Proton Accelerator Research Complex rapid cycling synchrotron

Abstract The Japan Proton Accelerator Research Complex (J-PARC) Rapid Cycling Synchrotron (RCS) employs magnetic alloy (MA) loaded cavities. We realize multi-harmonic rf driving and beam-loading compensation owing to the broadband characteristics of the MA. The currently installed cavity is the conventional type, which is designed to be driven by tube amplifiers in a push–pull operation. The push–pull operation has some advantages, i.e., suppressing a higher harmonic distortion without the beam acceleration and shortening the cavity length. However, a disadvantage arises at the high intensity beam acceleration where the multi-harmonic rf driving causes a severe imbalance of the anode voltage swing and restricts the tube operation. Although we have achieved an acceleration for the design beam power of 1 MW, the imbalance becomes an issue in increasing the beam power further. We have developed a single-ended MA cavity to avoid such difficulty. The cavity has no tube imbalance intrinsically and it is found that the power consumption to drive the cavity can be reduced compared with the conventional one.

Liquid‐State Cathode Enabling a High‐Voltage and Air‐Stable Fe‐Al Hybrid Battery

AbstractAluminum (Al) is an ideal anode material in low‐cost battery system for energy storage, with high theoretical capacities. However, the sluggish Al3+‐involved kinetics challenges the selection of common cathode materials (Al3+ intercalation or conversion). Herein, a redox‐active Fe–Cl complex serves as the liquid‐state cathode to couple with a low‐cost Al anode, which synergizes the advantages of redox flow batteries and Al rechargeable batteries. The interplay of Fe‐Cl coordinated formula and electrochemical properties are revealed for the first time. It is found that [Fe2Cl7]− molecule has a high voltage versus Al anode (1.3 V), and the novel Fe‐Al hybrid battery fulfills a capacity of 1.6 mAh cm−2 (20 Ah L−1) record high in a coin cell among Al‐based batteries. Furthermore, the energy efficiency, which is a vital parameter to evaluate the energy cost of the energy storage technology, reaches 85% (superior to most Al‐based batteries) and an average of 70% over ≈900 h cycling. Particularly, the unique air‐stable character enables normal operation of the battery assembled in ambient air. This work establishes a new application scenario for Al anode toward low‐cost large‐scale energy storage.

Analysis of the effect of keeper working conditions on hollow cathode performance

Hollow cathodes are widely used in electric thrusters due to their high emission electron density and low maintained voltage. The hollow cathode performance may significantly change under different keeper working conditions. In this study, a series of ground experiments were carried out to study the effects of the keeper current and the distance between keeper and cathode top on the emission characteristics and plume structure of the hollow cathode. The experimental results show that the working state of the keeper electronic circuit is less likely to be disturbed by the anode electronic circuit when the ratio of keeper current to anode current rises up. The plasma potential does not always rise up with the emission current in the far-field (>6 cm) when the keeper current is not high (<3 A). The extend of the distance between keeper and cathode top forms a high obstacle to the anode electronic circuit, this obstacle not only causes an increase of anode voltage, but also leads to a significant discharge instability of hollow cathode. In this case, a higher keeper current and xenon flow rate are required to keep a stable working state of hollow cathodes. The experimental results contribute to research on the discharge instability mechanism of hollow cathodes and provide useful information for instructing hollow cathode design.

Application of Perforated Reference Electrodes in Small Cell Formats for Rate Tests and Electrochemical Impedance Spectroscopy

The use of reference electrodes (REs) in lithium‐ion batteries allows enhanced electrochemical analysis of individual electrodes via potential monitoring or electrochemical impedance spectroscopy (EIS). The previous publication presents a concept for a laser‐perforated RE (PRE). Herein, this PRE is applied in ≈60 mAh graphite/NMC811 pouch cells. Despite more than 17% of the electrode surface being covered by the PRE, only negligible capacity differences are observed for charge rates up to 2C compared to cells without PRE. At higher rates up to 5C, the blocking effect is present but stable. Reproducible and plausible anode voltage curves are obtained and the beginning of Li plating is detected. Cell EIS spectra are in good agreement with comparison cells without RE. The impedance spectra of the individual electrodes recorded by the PRE are confirmative and, with one exception, artifact‐free. The results demonstrate that our PRE can be reliably applied for investigating lab‐scale electrode coatings in small pouch cell formats.

Anodizing-induced cracking in the preparation of TiO2 nanotube arrays

Understanding structural integrity of physical structures in chemical and electrochemical systems/environments is of practical importance in analyzing and predicting the reliability and lifespan of the physical structures. In this work, we systematically investigate the crack growth in the TiO2 layers with TiO2 nanotube arrays during electrochemical anodization of Ti plates without external mechanical loading. There exists the combinational effects of the anodization voltage and the anodization temperature on the crack growth. A simple relationship between the growth rate of the areal crack density, the anodization temperature and the anodization voltage are proposed and supported by the experimental results. The growth rate of the areal density of the surface cracks increases with the increase of the anodization voltage and the anodization temperature. The nominal activation energy is a decreasing function of the anodization voltage, suggesting that increasing the anodization voltage promotes fast growth of the surface cracks in the TiO2 oxide layer.

Investigation of Conditions for Preparation of Ordered Nanohole Arrays by Anodization of Iron Substrates with Depression Patterns

Ordered iron oxide nanohole arrays were fabricated by the anodization of iron substrates with depression patterns formed by Ar ion milling with alumina masks in an ethylene glycol electrolyte containing NH4F and H2O. It was found that the optimization of anodization voltage, NH4F and H2O concentrations in the electrolyte, and electrolyte temperature is necessary to achieve straight pore growth induced from the depression patterns in the depth direction. The optimization of the anodization conditions enabled the formation of ordered iron oxide nanohole arrays with aspect ratios exceeding 10. The resulting ordered iron oxide nanohole arrays with high aspect ratios are expected to be applied to various functional devices such as photocatalysts and solar cells.

Experimental Study of the Effect of the Injection Locking on the Modulation Feature of Magnetron

The effect of the injection locking on the modulation feature of a continuous wave magnetron is demonstrated experimentally. The high-frequency signal is coupled to the power supply, via the designed coupling circuit, as the anode voltage ripple, which results in the amplitude modulation of the magnetron. The spectra of output microwave oscillations are measured after the reference signal is injected into the magnetron. The results of the measurements show that the injection locking cannot eliminate the sidebands caused by the high-frequency coupled modulation. Characteristics of modulation are not changed within the locking bandwidth although the injection frequency varies. The amplitude of sidebands is basically not changed with variation in the injection ratio. Finally, the relationship between the injection locking and the anode voltage ripple frequency is demonstrated qualitatively.

Transparent Flat Panel X-Ray Source Using ITO Transmission Anode and ZnO Nanowire Cold Cathode

X-ray sources have important applications in medical diagnosis, industrial inspection, etc. Transparent X-ray source has not been reported before, which enables the applications such as simultaneous imaging using X-ray and visible light. In this article, a fully vacuum-encapsulated transparent flat-panel X-ray source was prepared by using ZnO nanowires cold cathode and indium-tin-oxide (ITO) transmission anode. The effect of thicknesses of ITO film on X-ray radiation intensity was studied. A radiation dose rate of 6.85 mGy/s measured at 5 cm in front of the flat-panel X-ray source (FPXS) under 48-kV anode voltage and an optical transmittance of 72.63% at 550-nm light were achieved. X-ray spectra show the indium is the main element to generate the X-ray. By adopting the device in an X-ray and visible light dual-functional inspection set-up, the X-ray and visible light imaging of objects were demonstrated simultaneously.

Simulation of Anodic Current and Optimization of the Fitting Equation and the Fitting Algorithm during Constant Voltage Anodization

To investigate the formation mechanism of anodization and to clarify the relationship between the reaction process and the actual structure, we fitted the current density–time curve based on MATLAB. A time-varying function C(t) is introduced to optimize the total current fitting equation used to describe the constant voltage anodization process, which makes the equation more in line with the real reaction process based on the kinetic model of ionic and electronic current. Besides, a new fitting algorithm is developed based on the trust region method, which can effectively improve the fitting effect through iteration. In our work, the initial values of the parameters in the equation were calculated, and finally, the fitting degree of the constant voltage anodization under 40, 50, and 60 V was improved to 0.9842, 0.9693, and 0.9305, respectively. According to the new equation, the fitting degree of the total amount of charge transferred by ions during the reaction and the volume of oxides according to a proportional function can reach 0.9972.

Controlled growth of titanium dioxide nanotubes for doxorubicin loading and studies of in vitro antitumor activity.

Titanium dioxide (TiO2) materials are suitable for use as drug carriers due to their natural biocompatibility and nontoxicity. The aim of the study presented in this paper was to investigate the controlled growth of TiO2 nanotubes (TiO2 NTs) of different sizes via an anodization method, in order to delineate whether the size of NTs governs their drug loading and release profile as well as their antitumor efficiency. TiO2 NTs were tailored to sizes ranging from 25nm to 200nm according to the anodization voltage employed. The TiO2 NTs obtained by this process were characterized using scanning electron microscopy, transmission electron microscopy, and dynamic light scattering The larger TiO2 NTs exhibited greatly improved doxorubicin (DOX)-loading capacity (up to 37.5wt%), which contributed to their outstanding cell-killing ability, as evidenced by their lower half-maximal inhibitory concentration (IC50). Comparisons were carried out of cellular uptake and intracellular release rates of DOX for large and small TiO2 NTs loaded with DOX. The results showed that the larger TiO2 NTs represent a promising therapeutic carrier for drug loading and controlled release, which could improve cancer treatment outcomes. Therefore, TiO2 NTs of larger size are useful substances with drug-loading potency that may be used in a wide range of medical applications.

Sealing effect on corrosion resistance of boric sulfuric acid anodizing on AA2024

Aluminum is widely used due to its excellent properties, lightweight and thermal conductivity. However, when used in aircraft applications, it can cause corrosion and sticking, compromising safety. To address this issue, anodizing is used to improve aluminum's corrosion resistance and adhesion. In this study, the AA2024 material was anodized using the boron-sulfuric acid anodization (BSAA) process, followed by a sealing process using acetic acid. This sealing process forms an oxide layer on the aluminum's surface, which reduces the corrosion rate. The study investigated the effects of anodization voltage and time on the results of BSAA anodization through quantitative and qualitative measurements, including corrosion resistance, potentiodynamic polarization, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The results showed that samples anodized with a gasket could reduce the corrosion rate by up to 85 % compared to those without a gasket and substrate. The most significant reduction in corrosion rates occurred at an anodization voltage of 10 V and an anodization time of 15 min. The potentiodynamic test results indicated that the Tafel plot during sealing lies in the cathodic region where the corrosion current density decreases with increasing voltage. SEM observations revealed that the anodizing process could provide an oxide layer on the samples' surface, while the sealing process creates a smooth surface. EDS analysis showed that an oxide compound was formed in an oxide bond state after the sample surface was subjected to the sealing treatment. Overall, the study demonstrates the effectiveness of BSAA anodization in improving corrosion resistance and highlights the importance of considering the anodization parameters

Proof-of-Concept Vacuum Microelectronic NOR Gate Fabricated Using Microelectromechanical Systems and Carbon Nanotube Field Emitters.

This paper demonstrates a fully integrated vacuum microelectronic NOR logic gate fabricated using microfabricated polysilicon panels oriented perpendicular to the device substrate with integrated carbon nanotube (CNT) field emission cathodes. The vacuum microelectronic NOR logic gate consists of two parallel vacuum tetrodes fabricated using the polysilicon Multi-User MEMS Processes (polyMUMPs). Each tetrode of the vacuum microelectronic NOR gate demonstrated transistor-like performance but with a low transconductance of 7.6 × 10-9 S as current saturation was not achieved due to a coupling effect between the anode voltage and cathode current. With both tetrodes working in parallel, the NOR logic capabilities were demonstrated. However, the device exhibited asymmetric performance due to differences in the CNT emitter performance in each tetrode. Because vacuum microelectronic devices are attractive for use in high radiation environments, to test the radiation survivability of this device platform, we demonstrated the function of a simplified diode device structure during exposure to gamma radiation at a rate of 45.6 rad(Si)/second. These devices represent a proof-of-concept for a platform that can be used to build intricate vacuum microelectronic logic devices for use in high-radiation environments.

Simultaneous removal of microplastics and benzalkonium chloride using electrocoagulation process: statistical modeling and techno-economic optimization.

Microplastics and benzyldimethyldodecylammonioum chloride (DDBAC) enter the environment more frequently during the COVID-19 pandemic and their co-occurrence will be a potential threat to the environment in the post-pandemic era. This study investigates the performance of an electrochemical system for the simultaneous removal of microplastics and DDBAC. During experimental studies, effects of applied voltage (3-15V), pH (4-10), time (0-80min), electrolyte concentration (0.01-0.0.09M), electrode configuration, and perforated anode were investigated to identify their influence on DDBAC and microplastics removal efficiency. Eventually, the techno-economic optimization yielded to evaluate the commercial feasibility of this process. The central composite design (CCD) and analysis of variance (ANOVA) are employed for evaluation and optimization of the variables and response, DDBAC-microplastics removal, and for determining the adequacy and significance of mathematical models proposed by response surface methodology (RSM). Experimental results indicate that optimum conditions are pH = 7.4, time = 80min, electrolyte concentration = 0.05M, and applied voltage = 12.59, in which the removal of microplastics, DDBAC, and TOC reached the maximum level, which was 82.50%, 90.35%, and 83.60% respectively. The results confirm that the valid model is adequately significant for the target response. Overall, financial and energy consumption analyses confirmed that this process is a promising technology as a commercial method for the removal of DDBAC-microplastics complexes in water and wastewater treatment.

Application of a flexible memristor in self-color electronics and its depth mechanism analysis

Memristor has a high-density information storage capability and can manipulate a large amount of data computing in parallel, so it can be applied in neuromorphic computing. The advanced intelligent applications are one of the major breakthroughs made in the past decade based on the memristor's research. In this work, amorphous Nb2O5 film as functional layers on flexible niobium (Nb) foil were fabricated by anodic oxidation in oxalic acid aqueous solution. A broad spectrum of well-defined color was acquired by varying the anodic voltage during oxidation of the Nb foil. The results of spectroscopic ellipsometry (SE) tests show that the Nb2O5 layers with various colors have different thickness. The willow yellow Nb2O5 film with a thickness of ∼85 nm based memristor show an excellent memristive memory behavior. Finally, it was proposed that the potential well of the ionization center tilts under the external electric field, which causes the probability of charge to escape along and against the direction of the external electric field to explain the memristive effect of the device. This work opens up a new method for fabricating the flexible memristor, which provides the potential applications for next generation self-color electronics.

Highly Reliable Temperature Sensor Based on p-GaN/AlGaN/GaN Hybrid Anode Diode with Wide Operation Temperature from 73 K to 573 K

A high-performance temperature sensor based on a p-GaN/AlGaN/GaN hybrid anode diode (HPT-HAD) fabricated by hydrogen plasma treatment is demonstrated. The sensor exhibits accurate and stable temperature responses from 73 to 573 K. The forward anode voltage is linearly proportional to the temperature over the measured temperature range at a fixed current. At a forward current density of 10−7 mA/mm, the device achieves a maximum sensitivity of 1.93 mV/K. The long-time anode current stress measurement reveals that the HPT-HAD shows almost no degradation even at 573 K for 1 h at a current of 100 μA, and the anode voltage shifts only 120 mV at 573 K for 1000 s at 1 nA. This work shows that the HPT-HAD temperature sensor can be reliably operated over a wide temperature range from cryogenic to high temperatures, so can be used in a variety of extreme environments.

Structural parameters, optical band gap, and catalytic performance of anodized molybdenum

In this work, a nanopowder of porous molybdenum (Mo) oxides with different polymorphs were prepared by anodizing the Mo sheet in ethylene glycol solution containing fluoride at 60, 70, and 80 V for 30 min. Synthesized Mo oxides showed remarkable changes in their structural parameters and morphology upon the anodization voltage which were confirmed using X-ray diffraction, energy dispersive X-ray, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, N2 adsorption-desorption, and field emission scanning electron microscopic. Anodized Mo is composed of α-MoO3, β-MoO3, β-MoO2, and β-Mo9O26 phases. Synthesized Mo oxides were used, as a catalyst, for the photodegradation of methylene blue (MB), and results were compared to the literature. The maximum observed efficiency, ∼65%, towards MB was achieved using anodized Mo at 70 V (MO70) under UV–visible irradiation for 85 min. The N2 adsorption-desorption analysis revealed that MO70 exhibits the smallest particle size and greatest surface area among other samples. The performance of MB adsorption was investigated using several kinetic adsorption models and the pseudo-second-order model being the ideal one. The maximum adsorption constant is 1.4 × 10−2 g/(mg min) and the amount of MB that degraded at equilibrium is 5.52 mg/g for MO70. The anodization of Mo generated various polymorphs semiconductors which provide an excellent platform for the removal of toxic organic dyes from the wastewater.

Study on the ionization and acceleration of a microwave discharge cusped field thruster

The microwave discharge cusped field thruster is a novel concept electric micro propulsion device, also a candidate thruster for the gravitational detection mission. A coaxial transmission line resonator is utilized to feed the microwave into the thruster to generate Xe plasma steadily with a mass flow rate as low as 0.1 sccm. Due to the separation of ionization and acceleration, the thruster performs high operation mode stability over a wide range of voltage in low mass flow conditions. Experimental and simulation methods are carried out to study the ionization and ion acceleration of the thruster. The results show that in operating conditions with a mass flow rate of 0.1 sccm, an anode voltage of 0 V to 1000 V, and a microwave power of 2 W, the right-hand circularly polarized wave (R wave) and the ordinary wave (O wave) play the most important role in the ionization process. The ion acceleration region locates around the exit magnetic separatrix, and the acceleration region tends to converge toward the separatrix as the anode voltage increases, resulting in an increased focus of the thruster plume and concentration of the ion energy distribution. Due to the separation of the ionization and acceleration regions, the thruster performs a divergence efficiency of 0.5–0.8, and an acceleration efficiency of 0.9.

Phase engineering of layered anode materials during ion-intercalation in Van der Waal heterostructures

Transition metal dichalcogenides (TMDs) are a class of 2D materials demonstrating promising properties, such as high capacities and cycling stabilities, making them strong candidates to replace graphitic anodes in lithium-ion batteries. However, certain TMDs, for instance, MoS2, undergo a phase transformation from 2H to 1T during intercalation that can affect the mobility of the intercalating ions, the anode voltage, and the reversible capacity. In contrast, select TMDs, for instance, NbS2 and VS2, resist this type of phase transformation during Li-ion intercalation. This manuscript uses density functional theory simulations to investigate the phase transformation of TMD heterostructures during Li-, Na-, and K-ion intercalation. The simulations suggest that while stacking MoS2 layers with NbS2 layers is unable to limit this 2H → 1T transformation in MoS2 during Li-ion intercalation, the interfaces effectively stabilize the 2H phase of MoS2 during Na- and K-ion intercalation. However, stacking MoS2 layers with VS2 is able to suppress the 2H → 1T transformation of MoS2 during the intercalation of Li, Na, and K-ions. The creation of TMD heterostructures by stacking MoS2 with layers of non-transforming TMDs also renders theoretical capacities and electrical conductivities that are higher than that of bulk MoS2.

Development and characteristics study of compact Penning ion source

A compact-size Penning ion source with a small discharge volume (1.24 cm3) is developed. It consists of two concentric cylinders of different heights that act as cathodes and one hollow cylindrical anode. A homogeneous magnetic field is achieved within the discharge volume with geometrical optimization of the ion source. As a result, dense plasma is generated at low discharge power. The dynamics of the pulse mode discharge at low pulse width and frequency of anode voltage are studied. A high discharge (hundreds of amperes) current pulse with low delay time and fast rise time is recorded. The ion source is equally efficient to operate in continuous as well as pulse modes of ionization for various gases. It is operated in a wide range of low pressure at low anode voltage. An extraction system is designed to extract ions efficiently in the axial direction at a variable extraction voltage. The beam current of 200 µA in continuous mode and 6 A fast pulse in the pulsed mode of discharge have been measured. Variable beam current can be extracted with variable extraction voltage for any potential application.

Demonstration and experimental characteristics of a water-vapor Hall thruster

Water is an attractive candidate for condensable propellants owing to its availability, handleability, and sustainability. This study proposes the use of water vapor as a propellant for a low-power Hall thruster, and experimentally demonstrates the feasibility of this proposal. Based on the performance estimation from the plume diagnostics, a thrust-to-power ratio of 19 mN/kW, specific impulse of 550–860 s, and anode efficiency of 5–8 % were obtained at an anode power of 233–358 W. From further efficiency analysis, the mass utilization efficiency of water was found to be the most deteriorated among the internal efficiencies compared to the conventional xenon propellant, which was consistent with the expectations from a small discharge current oscillation, large beam divergence, and increase in low-energy ions. Moreover, additional power loss via reactions unique to polyatomic molecules was indicated by evaluation of the ionization cost. In this experiment, the mass utilization efficiency was improved with an increase in the anode voltage from 200 to 240 V without degradation of the power utilization. This suggests that operating at a higher voltage is more suitable for a water-vapor Hall thruster.