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We report a liquid metal microstrip antenna on a printing paper whose resonant frequency was tunable by folding the paper. The gallium-based alloy was used as liquid metal, which is instantly oxidized in ambient air. The oxidized liquid metal is easily wettable on printing paper surfaces, while it is non-wettable on laser-printed toner surfaces. An antenna with a 3 mm wide and 39 mm long copper-liquid metal overlapped-feedline linked to the liquid metal microstrip rectangle-shaped patch (40 × 31 mm2) was designed. The antenna pattern was printed on a printing paper using a laser printer. A liquid metal soaked roller was rolled on the antenna pattern printed paper, resulting in a liquid metal pattern where there was no toner. The resonant frequency of the liquid metal on the paper microstrip patch antenna was 2.88 GHz with −18.5 dB S11. The measured characteristics of the antenna were in good agreement with the simulation results. When the antenna was folded, the resonant frequency was changed to 2.68 GHz (x-axis folding) or 2.72 GHz (y-axis folding). Liquid metal on paper fabrication is simple but effective for creating custom-designed antennas that are easily re-designed and fabricated in the field. [ABSTRACT FROM AUTHOR]

Liquid metals such as gallium and its alloys can be printed on various substrates to form electronic circuits. However, up to now there are still few methods for the direct writing of liquid metals on common printed paper. Here, a novel conductive material prepared by adding metal powder to a gallium alloy is introduced. The proposed material exhibits low liquidity, excellent plasticity, significantly enhanced adhesivity to paper substrates, which guarantee the stable and flexible electrical connection. The oxide film wrapping the nickel powder forms a skeleton for additional oxidation products, resulting in superior adhesion to paper. In addition, several paper flexible electronic applications are showcased to demonstrate the practical value and reparability of this material. This work paves the way for the design of a facile method of preparing paper electronics. Liquid metals usually have poor wettability with printed paper. Here, mixture of nickel powder and EGaIn alloy (GIN) made by mixing EGaIn and nickel powder has low liquidity, excellent plasticity, and significantly enhanced adhesivity to paper substrates. Especially, an electrode cut by a sharp knife can be fixed simply. The superior and rapid repairable capability demonstrates the great potential of GIN material for practical application. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to explore the operating characteristics of gallium-based liquid metals (GLMs) by directly adding them as lubricants in real mechanical equipment. Design/methodology/approach: This paper conducts an analysis of the rotor-bearing system under GLM lubrication using a constructed test rig, focusing on vibration signals, surface characteristics of the friction pair, contact resistance and temperature rise features. Findings: The study reveals that GLM can effectively improve the lubrication condition of the tribo-pair, leading to a more stable vibration signal in the system. Surface analysis demonstrates that GLM can protect the sample surface from wear, and phase separation occurs during the experimental process. Test results of contact resistance indicate that, in addition to enhancing the interfacial conductivity, GLM also generates a fluid dynamic pressure effect. The high thermal conductivity and anti-wear effects of GLM can reduce the temperature rise of the tribo-pair, but precautions should be taken to prevent oxidation and the loss of its fluidity. Originality/value: The overall operating characteristics of the rotor-bearing system under GLM lubrication were investigated to provide new ideas for the lubrication of the rotor-bearing system. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2024-0067/ [ABSTRACT FROM AUTHOR]

In this paper, a beta-phase gallium oxide (β -Ga2O3) vertical FinFET with diamond-gate has been studied by Silvaco-ATLAS simulation. The diamond-gate structure achieves adjustable pin (p-insulator-n) junction owing to the diamond-SiO2-Ga2O3 heterostructure. This design also enhances heat dissipation by virtue of the high thermal conductivity of the diamond. Compared to conventional FinFETs, the diamond-gate FinFET (DG-FinFET) reduces the static operating temperature rise by around 17.30%. Additionally, due to its greater heat dissipation capacity, DG-FinFETs provide a 5.84% increase in current density at 1 kA cm−2 current density level. The structural changes in the diamond-gate also result in a significant reduction in the gate-source capacitance (C GS). At 1 MHz operating frequency and the same gate voltage, DG-FinFETs have 69.29% less gate-source charge (Q GS), 70.80% less charge/discharge delay time, 73.70% less switching loss, and 57.15% less conduction loss. Overall, the simulation and analysis presented in this work indicate a promising advancement of the DG-FinFET structure in high-power and rapid switching applications. [ABSTRACT FROM AUTHOR]

Background: The current strategies for making electronic devices are generally time, water, material and energy consuming. Here, the direct writing of composite functional circuits through comprehensive use of GaIn10-based liquid metal inks and matching material is proposed and investigated, which is a rather easy going and cost effective electronics fabrication way compared with the conventional approaches. Methods: Owing to its excellent adhesion and electrical properties, the liquid metal ink was demonstrated as a generalist in directly making various basic electronic components such as planar resistor, inductor and capacitor or their combination and thus composing circuits with expected electrical functions. For a precise control of the geometric sizes of the writing, a mask with a designed pattern was employed and demonstrated. Mechanisms for justifying the chemical components of the inks and the magnitudes of the target electronic elements so as to compose various practical circuits were disclosed. Results: Fundamental tests on the electrical components including capacitor and inductor directly written on paper with working time up to 48 h and elevated temperature demonstrated their good stability and potential widespread adaptability especially when used in some high frequency circuits. As the first proof-of-concept experiment, a typical functional oscillating circuit including an integrated chip of 74HC04 with a supply voltage of 5 V, a capacitor of 10 nF and two resistors of 5 kΩ and 1 kΩ respectively was directly composed on paper through integrating specific electrical elements together, which presented an oscillation frequency of 8.8 kHz. Conclusions: The present method significantly extends the roles of the metal ink in recent works serving as only a single electrical conductor or interconnecting wires. It opens the way for directly writing out complex functional circuits or devices on different substrates. Such circuit composition strategy has generalized purpose and can be extended to more areas, even daily pervasive electronics. [ABSTRACT FROM AUTHOR]

Through XRD analysis and xrayutilities fitting, this paper investigates the structural parameters of AlxGa1−xN(AlGaN) epitaxial layers grown on both free-standing GaN (FS-GaN) substrates and GaN templates (4.5 um GaN on Sapphire), including thickness and Al composition. These parameters determine the conductivity performance of GaN high electron mobility transistor devices. Under the same growth conditions, the Al composition in the AlGaN epitaxial layer grown on FS-GaN substrates is lower, but the thickness (growth rate) is higher, indicating a relatively weaker efficiency of Al substitution for Ga. This trend remains within a large range of trimethylgallium input ratios of 20%–40%. By analyzing and demonstrating the various differences between the two substrates, it can be concluded that the misorientation angle and threading dislocation density of the GaN layer have a high correlation with the efficiency of Al substitution, while the stress of the GaN layer and the temperature of the substrate surface show no significant correlation. [ABSTRACT FROM AUTHOR]

The large discrepancy among the nucleation kinetics extracted from experimental measurements and computer simulations and the prediction of the classical nucleation theory (CNT) has stimulated intense arguments about its origin in the past decades, which is crucially relevant to the validity of the CNT. In this paper, we investigate the atomistic mechanism of the nucleation in liquid Al in contact with amorphous substrates with atomic-level smooth/rough surfaces, using molecular dynamics (MD) simulations. This study reveals that the slightly distorted local fcc/hcp structures in amorphous substrates with smooth surfaces can promote heterogeneous nucleation through a structural templating mechanism, and on the other hand, homogeneous nucleation will occur at a larger undercooling through a fluctuation mechanism if the surface is rough. Thus, some impurities, previously thought to be impotent, could be activated in the homogeneous nucleation experiments. We further find that the initial growth of the nucleus on smooth surfaces of amorphous substrates is one order of magnitude faster than that in homogeneous nucleation. Both these factors could significantly contribute to the discrepancy in the nucleation kinetics. This study is also supported by a recent study of the synthesis of high-entropy alloy nanoparticles assisted with the liquid metal Ga [Cao et al., Nature 619, 73 (2023)]. In this study, we established that the boundary existed between homogeneous and heterogeneous nucleation, i.e., the structural templating is a general mechanism for heterogeneous nucleation, and in its absence, homogeneous nucleation will occur through the fluctuation mechanism. This study provides an in-depth understanding of the nucleation theory and experiments. [ABSTRACT FROM AUTHOR]

In order to realize direct manufacturing of cavity inside metal without assembly, this paper investigates the mechanism of cavity manufacturing inside metals under compound acoustic fields. First, a local acoustic cavitations model is established to study the single bubble generation at fixed point in Ga-In metal droplets, which has a low melting point. Second, cavitation-levitation acoustic composite fields are integrated with the experimental system for simulation and experimentation. Through COMSOL simulation and experimentation, this paper expounds the manufacturing mechanism of metal internal cavity under acoustic composite fields. The key problem is to control the duration of the cavitation bubble by controlling the driving acoustic pressure's frequency and the magnitude of ambient acoustic pressure. Under the condition of composite acoustic fields, this method realizes the direct fabrication of cavity inside Ga-In alloy for the first time. [ABSTRACT FROM AUTHOR]

In this paper, increasing indium composition 'x' in quantum barriers of In0.15Ga0.85N/InxGa(1-x)N based laser diode structure is proposed. The paper analyses the effect of molar composition of indium in quantum barrier and geometrical variation of barrier thickness. Observations related to laser power characteristics, material strain, band diagram analysis and carrier density has been carried out in the modified structures. Laser power has experienced an increment from 126 mW to ~ 172 mW in proposed laser diode structure as compared to the reference structure. The optical confinement factor of the active region has improved from 0.94% to 1.33%. The electron potential barrier height has upsized from 171 meV to 187 meV, while the hole potential barrier height has downsized from 150 meV to 135 meV at 120 mA injection current. Analysis of increasing indium composition in quantum barriers has been laid out to examine the effect of epitaxial symmetry in the device structure. [ABSTRACT FROM AUTHOR]

In this paper, we report the molecular beam epitaxy-grown InGaN-quantum disks embedded within selective area epitaxy of GaN nanowires with both Ga- and N-polarities. A detailed comparative analysis of these two types of nanostructures is also provided. Compared to Ga-polar nanowires, N-polar nanowires are found to exhibit a higher vertical growth rate, flatter top, and reduced lateral overgrowth. InGaN quantum disk-related optical emission is observed from nanowires with both polarities; however, the N-polar structures inherently emit at longer wavelengths due to higher indium incorporation. Considering that N-polar nanowires offer more compelling geometry control compared to Ga-polar ones, we focus on the theoretical analysis of only N-polar structures to realize high-performance quantum emitters. A single nanowire-level analysis was performed, and the effects of nanowire diameter, taper length, and angle on guided modes, light extraction, and far-field emission were investigated. These findings highlight the importance of tailoring nanowire geometry and eventually optimizing the growth processes of III-nitride nanostructures. [ABSTRACT FROM AUTHOR]

The need for new heat transfer agent for many applications, namely in the consumer electronics industry, requires materials, liquids at room temperature, with high thermal conductivity. From the different possibilities, Galinstan, a eutectic alloy of Gallium, Indium, and Tin with a melting point (Tm = 283.4 K) has been proposed for many applications, namely for replacing the toxic mercury element, used for many years. It is the purpose of this paper to report thermal conductivity measurements of Galinstan, product name Gallium/Indium/Tin Eutectic (NL-011), Ga68.4In21.5Sn10. The method used was the transient hot strip (THS), using a platinum metal-film sensor, produced by PVD in ceramic substrates, and electrically insulated with a heat-shrinkable coating. The details of the data acquisition system and measuring procedure are reported. Measurements were performed between 28 °C and 103 °C (301 K to 376 K), at atmospheric pressure, with an estimated uncertainty of 6%, and compared with available literature. Data were correlated for linear interpolation. This type of sensor is applied to molten metals for the first time, proofing to concept to future applications in molten metals and molten salts at higher temperatures. [ABSTRACT FROM AUTHOR]

With the rising demand for implantable orthopaedic medical devices and the dominance of device-associated infections, extensive research into the development of novel materials has been prompted. Among these, new-generation titanium alloys with biocompatible elements and improved stiffness levels have received much attention. Furthermore, the development of titanium-based materials that can impart antibacterial function has demonstrated promising results, where gallium has exhibited superior antimicrobial action. This has been evidenced by the addition of gallium to various biomaterials including titanium alloys. Therefore, this paper aims to review the antibacterial activity of gallium when incorporated into biomedical materials, with a focus on titanium-based alloys. First, discussion into the development of new-generation Ti alloys that possess biocompatible elements and reduced Young's moduli is presented. This includes a brief review of the influence of alloying elements, processing techniques and the resulting biocompatibilities of the materials found in the literature. The antibacterial effect of gallium added to various materials, including bioglasses, liquid metals, and bioceramics, is then reviewed and discussed. Finally, a key focus is given to the incorporation of gallium into titanium systems for which the inherent mechanical, biocompatible, and antibacterial effects are reviewed and discussed in more detail, leading to suggestions and directions for further research in this area. [ABSTRACT FROM AUTHOR]

The rapid evolution of wireless communication systems toward 6G demands efficient antennas with the features of adaptability and versatility. Liquid antennas have gained significant research interest due to their unique features in realizing small, flexible, transparent, and reconfigurable antennas for promising applications in future wireless systems. In this paper, in order to find a suitable metallic liquid for effective antennas, we design and compare the performance of metallic liquid antennas using Mercury, gallium indium alloy (EGaIn), and Graphene metallic liquid in the sub-6 GHz frequency. The antenna is realized by the metallic liquid in a poly methyl methacrylate microfluidic channel over a liquid crystal polymer substrate at 5.6 GHz frequency. The performance of these metallic liquid antennas is analyzed by their electromagnetic and radiation performance. The Graphene-based metallic liquid antenna shows better electromagnetic performance in comparison to Mercury and EGaIn metallic liquid antennas. [ABSTRACT FROM AUTHOR]

A co-sputtering process for the deposition of Fe0.8Ga0.2B alloy magnetostrictive thin films is studied in this paper. The soft magnetic performance of Fe0.8Ga0.2B thin films is modulated by the direct-current (DC) sputtering power of an FeGa target and the radio-frequency (RF) sputtering power of a B target. Characterization results show that the prepared Fe0.8Ga0.2B films are amorphous with uniform thickness and low coercivity. With increasing FeGa DC sputtering power, coercivity raises, resulting from the enhancement of magnetism and grain growth. On the other hand, when the RF sputtering power of the B target increases, the coercivity decreases first and then increases because of the conversion of the films from a crystalline to an amorphous state. The lowest coercivity of 7.51 Oe is finally obtained with the sputtering power of 20 W for the FeGa target and 60 W for the B target. Potentially, this optimization provides a simple way for improving the magnetoelectric coefficient of magnetoelectric composite materials and the sensitivity of magnetoelectric sensors. [ABSTRACT FROM AUTHOR]

This paper describes the realization of a soft, flexible, coil fabricated by means of a liquid metal alloy encased in a biocompatible elastomeric substrate for operation in a telemetry system, primarily for application to biomedical implantable devices. Fluidic conductors are in fact well suited for applications that require significant flexibility as well as conformable and stretchable devices, such as implantable coils for wireless telemetry. A coil with high conductivity, and therefore low losses and high unloaded Q factor, is required to realize an efficient wireless telemetry system. Unfortunately, the conductivity of the liquid metal alloy considered-eutectic gallium indium (EGaIn)-is approximately one order of magnitude lower than gold or copper. The goal of this paper is to demonstrate that despite the lower conductivity of liquid metal alloys, such as EGaIn, compared with materials, such as copper or gold, it is still possible to realize an efficient biomedical telemetry system employing liquid metal coils on the implant side. A wireless telemetry system for an artificial retina to restore partial vision to the blind is used as a testbed for the proposed liquid metal coils. Simulated and measured results show that power transfer efficiency of 43% and 21% are obtained at operating distances between coils of 5 and 12 mm, respectively. Further, liquid metal based coil retains more than 72% of its performance (voltage gain, resonance bandwidth, and power transfer efficiency) when physically deformed over a curved surface, such as the surface of the human eye. This paper demonstrates that liquid metal-based coils for biomedical implant provide an alternative to stiff and uncomfortable traditional coils used in biomedical implants. [ABSTRACT FROM PUBLISHER]

The so-called cellular magnetic domain structure has been widely observed in Fe–Ga alloys of different compositions and heat treatment. It has attracted attention for producing desirable magnetic properties and also for arousing controversy over its cause and identity. Two existing models, one based on novel charge density waves and the other based on traditional V-lines from the classical magnetic domain theory, give contradictory interpretations of the cellular domains in Fe–Ga alloys, which remain to be clarified. The cellular domains observed in Fe–Ga alloys so far are highly periodic, consisting of parallel chains of rectangular cells. This paper reports on the presence of various deviations in the cellular domains from the previously known ideal periodic cellular structure in Fe–Ga alloys and explores the implications of those variations. The variations include changes in the cell shape, spacing, branching, and nesting. It is shown that the observed variations in the cellular domains can be explained well by the V-line model where the competition between elastic and wall energy drives the pattern formation process. In comparison, the disagreements of the charge density wave model with the experimental observations are addressed. Similar cellular domain variations observed previously in Fe–Si alloys are also discussed, confirming the generic aspects of the cellular domains and their variations in cubic magnetostrictive materials. The findings provide insights into the magnetic domain phenomena in Fe–Ga alloys. [ABSTRACT FROM AUTHOR]

In this paper, we present studies relating to the structural, electronic, magnetic and mechanical properties of TiHfFeX (X = Al , Ga, In) full Heusler alloys. We will use the GGA-PBE, TB-mBj, GGA-PBEsol, and GGA-WC approximation implemented in the density functional of the theory as integrated into the Wien2k software. However, the full Heusler alloys studied are considered in the ferromagnetic phase for different structural stabilities of the TiHfFeAl, TiHfFeGa and TiHfFeIn phases. types I, II or III, respectively. Calculation of band structures and total electron density of states shows that these alloys can both exhibit topologically non-trivial semi-metallic characteristics with energy bandgaps of 0.010 eV, 0.014 eV and 0.018 eV. The electronic stability of 'such a Heusler structure will have nothing to do with its mechanical stability. Calculations reveal that the systems exhibit semi-metallic ferromagnetism. The elastic constants and the associated elastic moduli confirm its stability given by different elastic constants namely the Cauchy pressure, Poisson's ratio, the anisotropy factor, Young's modulus and the shear modulus. [ABSTRACT FROM AUTHOR]

Stretchable supercapacitors (SCs) have attracted attention as energy storage devices for wearable electronics due to their excellent power performance, low heat generation, and ease of integration into clothing. This paper presents a stretchable SC composed of liquid metal current collectors on textile substrates. For the liquid metal and textile‐based supercapacitors (LM/Tex SCs), the wetting characteristics and electrical resistance of the liquid metal on different types of textile substrates are investigated. The wettability of the carbon nanotube suspension for an electrochemically active material is also affected by the chemical and structural properties of the textile substrates. The intrinsically stretchable LM/Tex SCs are fabricated by sandwiching a soft gel electrolyte layer between the two liquid metal and textile‐based electrodes. The optimized SCs based on the polyester/neoprene textile exhibit a high areal capacitance of 527.8 mF cm−2 and maintain more than 90% of their initial capacitance after 1000 repetitive stretching cycles. Finally, it is demonstrated that the LM/Tex SC is readily integrated into a shirt and reliably supplies electrical energy to light up a light‐emitting diode even under human motion. [ABSTRACT FROM AUTHOR]

Gallium oxide (β-Ga2O3) is a well-known extra-wide bandgap semiconductor and one of the promising materials used for power photoelectric devices, gas sensors, catalytic agents, etc. This work presents the suppression of self-trapped holes (STHs) and increase of oxygen vacancies (VO) in β-Ga2O3 microspindles by doping of Zn ions as well as the electrocatalytic activity of these microspindles. Undoped and Zn-doped β-Ga2O3 microspindles were prepared by a hydrothermal method followed by high-temperature calcination. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results show that the morphology and structure of the samples did not change after low dose of Zn doping. The analyses of temperature-dependent photoluminescence (PL) spectra and X-ray photoelectron spectroscopy (XPS) indicate that incorporation of divalent Zn ions as deep acceptors can increase VO concentration and effectively suppress the formation of STHs. Enhanced electrocatalytic activity was observed in Zn-doped β-Ga2O3 microspindles compared with undoped β-Ga2O3 microspindles. The new active sites introduced by Zn doping, higher VO concentration, and suppressed STHs are believed to be responsible for the enhanced electrocatalytic performance of Zn-doped β-Ga2O3 microspindles. This work is expected to expand the application of β-Ga2O3 based microstructures in electrocatalysis and provide innovative ideas for energy and environmental issues. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the Al2O3/GaN critical buried interface of the next generation of gallium nitride (GaN)‐based transistors using time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and hard X‐ray photoelectron spectroscopy (HAXPES). Results highlight that gallium oxidation at this interface is enhanced when increasing the Al2O3 thickness from 3 up to 20 nm. Gallium oxidation is reduced when using both O3 and H2O as oxidant precursors, compared with only H2O during the growth of Al2O3. In addition, the O3/H2O‐based Al2O3 favors a reduction of contaminants such as hydrogen and carbon but enhances the presence of halides (Cl− and F−) at this Al2O3/GaN interface. [ABSTRACT FROM AUTHOR]

GaxIn1−xAs–GaAsySb1−y type-II superlattices (T2SLs) have recently received broad attention as an InP-based optical absorption layer in short-wavelength infrared detectors. However, the cut-off wavelength of a GaInAs–GaAsSb T2SL detector is ordinarily around 2.4 µm at room temperature. This paper proposes extending the cut-off wavelength using a GaAs/InAs digital alloy instead of a GaxIn1-xAs random alloy layer in a GaxIn1−xAs–GaAsySb1−y T2SL. The calculation result employing an empirical sp3d5s* tight-binding method has revealed that a (GaAs/InAs)–GaAsySb1−y digital alloy T2SL on an InP substrate possesses a band gap corresponding to a wavelength of 2.9 µm which is over 0.4 µm longer than that in a conventional GaInAs–GaAsSb T2SL at a temperature of 200 K. Figured optical absorption coefficient spectra of certain digital alloy T2SLs, e.g., a [(GaAs)4(InAs)4]2–(GaAs0.53Sb0.47)17 structure, present a considerable polarization-direction dependence—originating from the asymmetrical shape of the wavefunction in the quantum well. Yet, by altering the atomic layer configuration in the growth direction of the digital alloy T2SL to have such a quantum well structure with a reflection symmetry as in [(GaAs)4(InAs)4]2(GaAs)3–(GaAs0.45Sb0.55)17, the polarization dependency can be dramatically decreased due to the symmetry improvement of the wavefunction. [ABSTRACT FROM AUTHOR]

The traditional blade cooling method can no longer meet the requirements of high cooling efficiency in modern engines. In order to solve this cooling problem, this paper proposes cooling turbine guide blades based on liquid metal. The feasibility was preliminarily verified using a one-dimensional heat conduction model. Then, using a numerical method, we found that the cooling effect of liquid metal is much better than that of air cooling. The main reason for its good cooling effect is that the heat transfer coefficient of liquid metal reaches a magnitude of tens of thousands. Moreover, as the inlet temperature of the liquid metal decreases and the inlet Reynolds number increases, the liquid cooling effect becomes better. The definition of the heat transfer quality factor can reflect the reasons for the influence of the inlet temperature of the liquid metal. [ABSTRACT FROM AUTHOR]

Ultra-wide bandgap semiconductor gallium oxide (Ga2O3) features a breakdown strength of 8 MV/cm and bulk mobility of up to 300 cm2V−1s−1, which is considered a promising candidate for next-generation power devices. However, its low thermal conductivity is reckoned to be a severe issue in the thermal management of high-power devices. The epitaxial integration of gallium oxide thin films on silicon carbide (SiC) substrates is a possible solution for tackling the cooling problems, yet premature breakdown at the Ga2O3/SiC interface would be introduced due to the relatively low breakdown strength of SiC (3.2 MV/cm). In this paper, the on-state properties as well as the breakdown characteristics of the Ga2O3-on-SiC metal-oxide-semiconductor field-effect transistor (MOSFET) were investigated by using the technology computer-aided design (TCAD) approach. Compared with the full-Ga2O3 MOSFET, the lattice temperature of the Ga2O3-on-SiC MOSFET was decreased by nearly 100 °C thanks to the high thermal conductivity of SiC. However, a breakdown voltage degradation of >40% was found in an unoptimized Ga2O3-on-SiC MOSFET. Furthermore, by optimizing the device structure, the breakdown voltage degradation of the Ga2O3-on-SiC MOSFET is significantly relieved. As a result, this work demonstrates the existence of premature breakdown in the Ga2O3-on-SiC MOSFET and provides feasible approaches to further enhance the performance of hetero-integrated Ga2O3 power devices. [ABSTRACT FROM AUTHOR]

In this paper, a neural network model is introduced, which uses Convolutional Neural Network model optimized by Genetic Algorithm (GA-CNN) to predict the liquid level fluctuation of continuous casting mold in real time. The experimental data were obtained from the practical production process of an iron and steel plant in China. For the two-stream continuous caster in this factory, two sets of mold liquid level fluctuation value data sets were established. These data sets are categorized into the first- and the second-stream mold liquid surface fluctuation data set. Both data sets comprise 138 production parameters along with the mold liquid level fluctuation values. Random Forest feature screening and data preprocessing are carried out on the data set, so that the processed data can be learned and trained by the model, thus obtaining the mold liquid level fluctuation prediction model. To facilitate the analysis, the sensitivity analysis of related continuous casting production parameters and mold level fluctuation data was carried out. Subsequently, the influence of production parameters on the fluctuation value of mold liquid level was investigated by characteristic thermal diagram and Shapley additional explanations diagram, and the influence degree of each parameter on the model performance was determined. The results indicate that the GA-CNN model demonstrates strong predictive capability, with a high correlation coefficient (R2) of 0.98, a low mean absolute error (MAE) of 0.1093, and a mean square error (MSE) of 0.0225. Notably, the position of the stopper was identified as a critical factor significantly affecting mold level fluctuations. The model has high prediction accuracy and can meet the needs of practical application in steel plants. [ABSTRACT FROM AUTHOR]

The efficient hydrogen-production through the Aluminum-water reaction has become a prominent subject of interest. The impediment encountered in the reaction can be effectively alleviated by Aluminum-based alloy. In this study, density functional theory (DFT) was utilized to explore the mechanism of water decomposition stage on the surface of aluminum and gallium alloy (AGA). Through surface reaction calculations of 12 stable AGA configurations, it was gradually revealed that the optimal alloy ratio was gallium-to-aluminum at 3.5:1. Analysis of the density of states (DOS) indicated that the presence of gallium amplified the activity of surface aluminum. Moreover, frontier orbital theory and charge density maps confirmed that, due to the weak interaction between Ga and ions, the presence of H 2 inhibited Ga passivation, thereby enhancing the reactivity of AGA. This paper provided valuable insights into the surface reaction mechanisms of AGA using DFT, offering theoretical support for hydrogen production processes. • Density functional theory investigated the early stages of AGA-water reaction. • Modeling AGA (Ga proportions 73.8%–81.2%) yields 12 stable configurations. • Ga:Al = 3.5:1 exhibits highest energies for O 2 , H 2 O, and co-adsorption. • Ga enhances AGA's catalytic activity, shown in DOS graphs comparisons. • AGA plays dual roles in surface hydrogen dynamics. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of gallium oxide (Ga2O3) and hafnium dioxide (HfO2) thin films as interlayers between the Ni and n-GaN semiconductor on the electrical characteristics of the Ni/n-GaN Schottky junction (SJ). The X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) results confirmed that Ga2O3 and HfO2 films were formed on the n-GaN semiconductors. The electrical and transport carrier properties of the Ni/HfO2/Ga2O3/n-GaN metal/oxide/semiconductor (MOS) junction were obtained via current–voltage (I–V) measurements and compared with Ni/n-GaN Schottky junction in the voltage range from − 5 V to + 5 V at room temperature. In contrast to the SJ, the MOS junction displayed a superior rectifying nature and a lower reverse leakage current. The barrier height (Φb) and ideality factor values of the SJ and MOS junctions were estimated to be 0.58 eV and 1.21, and 0.75 eV and 1.06, respectively. A higher Φb was attained for the MOS junction compared to the SJ, which enabled the Ga2O3 and HfO2 interlayers to alter Φb. The Φb values are derived from the I–V, Hernandez, Cheung, and surface potential methods and the derived values were comparable to one another, which indicates their consistency and validity. The density of the interface state (NSS) of the MOS junction decreased compared to SJ, which indicates that the interlayers influence the NSS of the SJ boundary. The forward bias log (I) − log (V) curve of the SJ and MOS junction revealed the ohmic nature in low-voltage regimes and space-charge-limited conduction in high-voltage regimes. The results show that the Poole–Frenkel emission dominates the reverse leakage current of the SJ and MOS junction. These outcomes indicate that Ga2O3 and HfO2 films can be chosen as dielectric materials in the construction of MOS devices. [ABSTRACT FROM AUTHOR]

In the present paper, we have simulated the core–shell nanospheres of gallium and its alloy in different surrounding medium. The main thrust of this work is to analyze refractive index sensitivity of gallium-based nanoparticles towards LSPR-based biosensing applications. A consistent improvement in bulk refractive index sensitivity of 3–9% is noticed with optimized size of liquid metal-noble metal core–shell nanoparticle. Mielab software based on analytical solutions of vector wave equation presented in Mie theory is used to calculate extinction profile of considered nanoparticles. Ga, GaAg, and GaAl nanoparticles support strong and tunable resonance peaks in deep UV–visible region and exhibit higher sensitivity factor of 295.3 nm/RIU. The inflection point flanking around peak maxima to the longer wavelength side is observed to be most sensitive to change in dielectric environment. The three liquid metals studied can contribute to the emerging role of liquid metals in LSPR-based biosensors for flexible devices as well as can extend their use to DNA detection, chemodynamic therapeutics, photoacoustics etc. applications. [ABSTRACT FROM AUTHOR]

SF6/N2 gas mixture decomposition components can reflect the operation status inside GIS, and be used for fault diagnosis and monitoring inside GIS. NF3 and N2O are the characteristic decomposition components of SF6/N2 mixed gas. In order to find a potential gas sensitivity material for the detection of NF3 and N2O. This paper investigated the adsorption properties of NF3 and N2O on Al- and Ga- doped graphene monolayers based on density functional theory. Through the analysis of adsorption distance, charge transfer, adsorption energy, energy band structure, etc., the results indicated that the adsorption effect of Al- and Ga-doped graphene to NF3 and N2O are probably good, and these nanomaterials are potential to apply for the monitoring of GIS internal faults. [ABSTRACT FROM AUTHOR]

This paper reports on TCAD simulation of beta-gallium oxide (β-Ga2O3) MOSFET with the channel recessed into a 1-µm thick Si-doped (1 × 1018 cm−3) epitaxial layer. We optimized gate recess thickness to achieve both depletion mode (D-mode) and enhancement mode (E-mode) operations. The simulated β-Ga2O3 MOSFET structures show optimum D-mode and E-mode characteristics for 150-nm and 15-nm active channel thicknesses, respectively. A comparative study is also done to analyze the thermal and electrical effects by simulating the heteroepitaxial β-Ga2O3 layer on sapphire substrate [201] and homoepitaxial β-Ga2O3 layer on β-Ga2O3 [010] substrate. The MOSFET devices based on the β-Ga2O3 layers on sapphire substrates show improved performance compared to the devices based on the β-Ga2O3 layers on β-Ga2O3 substrates in terms of drain current, transconductance, and breakdown voltage. β-Ga2O3 epitaxial layers on sapphire substrates exhibit a drain current density of 425 mA/mm with a peak transconductance of 12.2 mS/mm for D-mode operation and 153 mA/mm drain current density with a peak transconductance of 20.8 mS/mm for E-mode operation. In contrast, the MOSFET devices based on the β-Ga2O3 epitaxial layers on β-Ga2O3 substrates show a drain current density of 415 mA/mm for D-mode operation and 144 mA/mm drain current density with 3.2 mS/mm peak transconductance for E-mode operation. The MOSFET devices based on the β-Ga2O3 epitaxial structures on sapphire and β-Ga2O3 substrates show reliable switching properties with improved subthreshold slope and high Ion/Ioff ratio of 1011. These simulation results show potential of laterally scaled β-Ga2O3 MOSFETs for power-switching applications. [ABSTRACT FROM AUTHOR]

In this paper, a flexible and stretchable energy harvester based on liquid-metal and fluorinated ethylene propylene (FEP) electret films is proposed and implemented for the application of wearable devices. A gallium liquid-metal alloy with a melting point of 25.0 °C is used to form the stretchable electrode; therefore, the inducted energy harvester will have excellent flexibility and stretchability. The solid-state electrode is wrapped in a dragon-skin silicone rubber shell and then bonded with FEP electret film and conductive film to form a flexible and stretchable energy harvester. Then, the open-circuit voltage of the designed energy harvester is tested and analyzed. Finally, the fabricated energy harvester is mounted on the elbow of a human body to harvest the energy produced by the bending of the elbow. The experimental results show that the flexible and stretchable energy harvester can adapt well to elbow bending and convert elbow motion into electric energy to light the LED in a wearable watch. [ABSTRACT FROM AUTHOR]

Various yellowish-green persistent phosphors of Y2.95−x−yLuxGdyAl5−zGazO12:0.05Ce3+ (x = 0–1, y = 0–1, z = 1–4) were successfully synthesized by the one-step high-temperature solid-state reaction method in air. The effects of simultaneous doping of Lu3+, Gd3+ and Ga3+ on the luminescence properties of the phosphors were investigated in detail for the first time. Herein, the microstructure, morphology, afterglow performance, luminescence properties, thermoluminescence, thermal quenching and flicker index of the efficient blue-light-activated Y2.95−x−yLuxGdyAl5−zGazO12:0.05Ce3+ phosphors were tested. The τ90 and τ80 values of Y1.45LuGd0.5Al2.5Ga2.5O12:0.05Ce3+ are 10.8 ms and 33.2 ms, respectively. These parameters are important in terms of effectiveness in reducing flicker in alternating current (AC) LEDs. Compared with the conventional Y3Al2Ga3O12:Ce3+ phosphor, the Y1.45LuGd0.5Al2.5Ga2.5O12:0.05Ce3+ phosphor has a better luminescence performance, stronger afterglow performance, and lower flicker index. The quantum yield of the Y1.45LuGd0.5Al2.5Ga2.5O12:0.05Ce3+ phosphor was 86.42% and the luminous efficiency of the LED devices prepared with it reached 92.12 lm W−1 when operated at 100 mA. Integrating sphere and spectroradiometer tests as well as CIE chromaticity diagrams indicate that the AC-WLEDs assembled by mixing the Y1.45LuGd0.5Al2.5Ga2.5O12:0.05Ce3+ phosphor and a commercial red phosphor in an appropriate ratio could obtain ideal white light with a high color-rendering index (87.9) and the flickering index was successfully reduced from 100% to 61.4%. [ABSTRACT FROM AUTHOR]

Recently, chalcogenides have attracted much attention as electrocatalysts in hydrogen evolution reaction (HER). However, few studies have been conducted on the electrocatalytic properties of gallium oxides and chalcogenides. In this paper, a Ga 2 XY (X ≠ Y, X, Y=O, S, Se, Te) defect structure doped by non-metal B, C, N, P, Si, and As have been designed. According to the study, the doping of non-metal atoms can significantly enhance their HER properties, the Ga 2 OSe-As Xi -Xi structure and Ga 2 SeTe-Si Xi -NM structure possess intensely excellent HER properties in this study with the Gibbs free energy of 0.01 eV and 0.00 eV, respectively. It is found that the Ga 2 SeTe structure has a more concentrated electron transfer range compared to the Ga 2 OSe structure, leading to a superior HER performance. This work provides a new idea for the study of HER electrocatalytic performance of the Ga 2 XY system, and it is expected to be applied to HER catalysts affordably and efficiently. • Screening of non-metal doped Ga 2 XY defective structures for HER electrocatalytic performance. • The introduction of Ga vacancies significantly enhances the HER performance of Ga 2 XY structures. • The Ga 2 SeTe defective doped structure has a more concentrated electron transfer range compared to the Ga 2 OSe structure. • The As-doped Ga 2 OSe structure and the Si-doped Ga 2 SeTe structure containing Ga defect have a near-zero ΔG H. [ABSTRACT FROM AUTHOR]

In this paper, a finite element method is proposed to predict the contact pressure of the metal seal in the subsea pipeline connector with regard of the penetration load on the critical sealing surface. Further, a fast GA-ANN model is proposed on the basis of GA-ANN to optimize the sealing structure of the connector, which uses only 3–6 % of the calculation time compared to the traditional GA-ANN model. The fast GA-ANN is further coupled with NSGA-II in the multiple objective optimization of the sealing structure and the results are compared with that of the response surface methodology (RSM). In terms of the number of valid candidate points and the optimal candidate point, NSGA-II coupled fast GA-ANN model performs much better than RSM. The hydrostatic pressure tests were carried out with the optimal sealing structure by the fast GA-ANN and the results meet the design requirements very well. [ABSTRACT FROM AUTHOR]

In this paper, we employed Density Functional Theory (DFT) to study structural and mechanical stability, electric, magnetic and electronic properties of cubic Co-based new quaternary half-Heusler alloys CoZrCrZ (Z = Al, Ga, In) using WIEN2k. Volume optimisation suggests that these alloys are stable in the Y1 structure and show ferromagnetic behavioTAur. Generalised Gradient approximation calculations confirm the half-metallic nature of the reported alloys, which show metallic nature, and semiconducting band gaps exist in spin-up and spin-down channels, respectively. From the calculated cubic elastic constants, the reported Heusler alloys shows ductile nature. The calculated spin-magnetic moments of CoZrCrZ (Z = Al, Ga, In) are consistent with the Slater-Pauling rule. The very fine narrow band gap in the spin-down channel enhances the thermoelectric properties. The reported ferromagnetic half-metals with good thermoelectric parameters suggests that these alloys have possible applications in spin-based electronics and green energy technology. [ABSTRACT FROM AUTHOR]

Rigid sensors are a mature type of sensor, but their poor deformation and flexibility limit their application range. The appearance and development of flexible sensors provide an opportunity to solve this problem. In this paper, a resistive flexible sensor utilizes gallium−based liquid metal (eutectic gallium indium alloy, EGaIn) and poly(dimethylsiloxane) (PDMS) and is fabricated using an injecting thin−line patterning technique based on soft lithography. Combining the scalable fabrication process and unique wire−shaped liquid metal design enables sensitive multifunctional measurement under stretching and bending loads. Furthermore, the flexible sensor is combined with the glove to demonstrate the application of the wearable sensor glove in the detection of finger joint angle and gesture control, which offers the ability of integration and multifunctional sensing of all−soft wearable physical microsystems for human–machine interfaces. It shows its application potential in medical rehabilitation, intelligent control, and so on. [ABSTRACT FROM AUTHOR]

The synergy between metals and metal oxides can effectively improve the heterogeneous catalytic process. This paper describes the intrinsic effect of Pt modification over GaOx (Pt−GaOx) on propane dehydrogenation. The presence of Pt promotes H2 dissociation and surface coverage of hydrogen species, which is beneficial for the activation of C−H in propane. With excessive Pt, Gaδ+ can be further reduced to form Pt−Ga alloy with less surface hydrogen species. Consequently, the relative propylene formation rate between Pt−GaOx and the summed contribution of individual Pt and GaOx increases linearly with the content of hydrogen species. Optimally, the relative propylene formation rate of Pt−GaOx with 0.03 wt % Pt exceeds 25 % of the summed contribution of individual components. [ABSTRACT FROM AUTHOR]

A circular surface wave (CSW) occurs in liquid metal layers as a rotational motion of the inclined upper surface and can be provided by different mechanisms in shaken and immovable vessels. In this paper we study experimentally the CSW of low-temperature gallium alloy in an immovable cell with a central bottom electrode and an upper ring electrode under an applied axial magnetic field. We confirm that a stationary CSW regime takes place if the forcing parameter exceeds some critical value. Above this value, the characteristic CSW frequency, normalized by the natural frequency of the azimuthal gravity wave in the same cell, approximately follows the law f / f 0 ∼ 1 + S / 2 , where S is the interaction parameter. The amplitude of surface oscillations also grows with the increase in forcing. The measured velocity profiles show that the flow has a complicated structure, and the calculations of the electromagnetic force distribution demonstrate that the stationary CSW in the considered problem is provided by the eccentric torque of the Lorentz force. [ABSTRACT FROM AUTHOR]

Gallium oxide, as an emerging semiconductor, has attracted a lot of attention among researchers due to its high band gap (4.8 eV) and a high critical field with the value of 8 MV/cm. This paper presents a review on different chemical and physical techniques for synthesis of nanostructured β-gallium oxide, as well as its properties and applications. The polymorphs of Ga2O3 are highlighted and discussed along with their transformation state to β-Ga2O3. Different processes of synthesis of thin films, nanostructures and bulk gallium oxide are reviewed. The electrical and optical properties of β-gallium oxide are also highlighted, based on the synthesis methods, and the techniques for tuning its optical and electrical properties compared. Based on this information, the current, and the possible future, applications for β-Ga2O3 nanostructures are discussed. [ABSTRACT FROM AUTHOR]

It is a key challenge to continuously power personal wearable health monitoring systems. This paper reports a novel liquid metal-enhanced wearable thermoelectric generator (LM-WTEG that directly converts body heat into electricity for powering the wearable sensor system. The gallium-based liquid metal alloys with room-temperature melting point (24~30 °C) and high latent heat density (about 500 MJ/m3) are used to design a new flexible finned heat sink, which not only absorbs the heat through the solid-liquid phase change of the LM and enhances the heat release to the ambient air due to its high thermal conduction. The LM finned is integrated with WTEG to present high biaxial flexibility, which could be tightly in contact with the skin. The LM-WTEG could achieve a super high output power density of 275 μW/cm2 for the simulated heat source (37 °C) with the natural convective heat transfer condition. The energy management unit, the multi-parameter sensors (including temperature, humidity, and accelerometer), and Bluetooth module with a total energy consumption of about 65 μW are designed, which are fully powered from LM-WTEG through harvesting body heat. [ABSTRACT FROM AUTHOR]

Zr, Ti and Ga-doped indium oxide (ITGZO) films with different structures were prepared by radio frequency (RF) magnetron sputtering method. The equiaxed–columnar stacked films which possess excellent carrier transport efficiency were designed, and their microstructure, electrical, optical and energy band properties were investigated systematically in this paper. The application of the stacked films has comprehensively improved the parameters of silicon heterojunction (SHJ) solar cells including series resistance (Rs), short-circuit current (Isc), fill factor (FF), and the final device efficiency (η). The gain in device performance mainly comes from three aspects: better crystalline quality, less grain boundary scattering, and the appropriate work function (WF). Furthermore, an interface modification layer with high carrier concentration was also used to improve the ITGZO/a-Si:H (hydrogenated amorphous silicon) interface carrier transport property. Benefit from this modification layer, the FF of SHJ solar cells increased from 77.71 to 81.51% and the Isc increased from 9.359 to 9.465 A. This work provides a feasible guidance for the structural design of transparent conductive oxide layer in SHJ solar cell. [ABSTRACT FROM AUTHOR]

The CMOS technology with MOSFETs below 70 nm node for Semiconductor Industry Association roadmap has outstanding resistance to short-channel effect and improves the scalability of the device. Cylindrical surrounding double-gate (CSDG) MOSFETs have been proposed as a suitable CMOS substitute to reduce the area and power tradeoff. This paper presents mathematical modeling of the electron density arrangement in the CSDG MOSFET for hybrid RF applications. In this device, the arbitrary alloy of Aluminum Gallium Arsenide (AlGaAs) has been used. This material lies between Aluminum Arsenide and Gallium Arsenide. High electron mobility and the lesser bandgap in AlGaAs make it suitable for the design of CSDG MOSFET for low-frequency applications. In the middle of CSDG MOSFET, the electron density (N2D) has been observed to be 1.92 × 1013 cm−2 for arbitrary alloy-based MOSFET and 1.02 × 1013 cm−2 for the conventional SiO2-based MOSFET towards the drain terminal. The electron density has been observed to be 7.90 × 1012 cm−2 for arbitrary alloy-based MOSFET and 5.86 × 1012 cm−2 for the conventional SiO2-based MOSFET along the channel. The results show that the average speed of the electron inside the device channel is submissive to the conventional MOSFET. [ABSTRACT FROM AUTHOR]

This paper presents a novel resonant magnetic sensor consisting of a graphene nanomechanical oscillator and magnetostrictive stress coupling structure, using Si/SiO2 substrate and Fe–Ga alloy, respectively. In this device, the deformation of the Fe–Ga alloy resulting from the external magnetic field changed the surface tension of the graphene, resulting in a significant change in the resonance frequency of graphene. Using the finite element analysis, it could be found that the response of the resonance frequency revealed a good linear relationship with the external magnetic field (along the x-axis) in the range of the 1 to 1.6 mT. By optimizing the sizes of each component of the magnetic sensor, such as the thickness of the Si/SiO2 substrate and the Fe–Ga alloy, and the length of the graphene, the sensitivity could even reach 834 kHz/mT, which is three orders of magnitude higher than conventional resonant magnetic devices. This provides a new method for highly sensitive and miniaturized magnetic sensors. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on the failure mechanism of high-current gallium arsenide photoconductive semiconductor switches (GaAs PCSSs) triggered by the laser diode. We propose a Blumlein pulse forming line to test the GaAs PCSS. The result shows that the damage of GaAs PCSS almost occurs at the anode under the circumstances that either anode or cathode is illuminated, since the highest amplitude of Gunn oscillation always occurs on the anode. We speculate that the failure of high-current GaAs PCSS is attributed to the Gunn effect according to the statistics about failure factors of GaAs PCSS. We use a scanning electron microscope to semiquantitatively analyze the compositions of the erosions microball or granules, which are gallium and arsenium. The result proves our speculation. [ABSTRACT FROM AUTHOR]

Wind turbine is the most effective power generation device. However, it works efficiently only in large-scale applications. Recent technological advancements in renewables and energy generation focus on harvesting kinetic energy from low-speed winds in much smaller regions, such as air-conditioning ducts. In this paper, we propose a simple wind vibrational power generator that utilizes magnetostrictive material to harvest electrical energy from low-speed wind. Magnetostrictive materials undergo large variations in magnetic flux upon the application of external force, such by wind-induced vibration, generating electromotive force. Our vibration power generator uses an iron–gallium (Fe–Ga) alloy, which has extremely high sensitivity and energy conversion efficiency. Through a wind tunnel experiment, the generator was confirmed to be suitable for power generation from low wind-speed regimes, such as air-conditioning ducts. The device used a wind receiving part made of a thin rectangular plate of polylactic acid (PLA) resin and a power generating part. It was achieved by passing a stream of wind around the plate to produce a vortex in its wake region and induce a cross-flow vibration, in which the device sensed and converted into electrical energy. In essence, vortex excitation helped in generating power even at near streamlined flow. [ABSTRACT FROM AUTHOR]

This paper presents a predictive model of subsurface damage depth hSSD and surface roughness in semi-consolidated abrasive grinding based on indentation fracture theory to rapidly and non-destructively detect subsurface damage of the workpiece. To verify the accuracy of the proposed model, cross-sectional microscopy was used to detect subsurface damage along the (100) and (010) crystal lographic planes in grinding of gallium oxide. In addition, the effects of grinding method, abrasive particle size, grinding pressure, and grinding disc speed on the damage along the (100) and (010) planes were analyzed. The results show a nonlinear relationship between the depth of the gallium oxide subsurface damage and surface roughness generated by semi-consolidated abrasive grinding. Under the same grinding conditions, the damage layer depth in semi-consolidated abrasive grinding is lower than in free abrasive grinding. When the same grinding method is used, the subsurface damage depth is greater along the (100) plane than along the (010) plane under the same grinding conditions. When the abrasive particle size is decreased from W14 to W3, the depth of the subsurface damage layer is reduced by 30% in semi-consolidated abrasive grinding. Reducing the grinding pressure can reduce the amount of subsurface damage, and the speed of the grinding disc also affects the subsurface damage of gallium oxide. The subsurface damage depth has little effect. After optimizing the grinding parameters, the surface roughness of gallium oxide along the (100) and (010) planes was 23 nm and 12 nm, respectively, and hSSD was 2.9 μm and 2.1 μm, respectively. The proposed model of the relationship between subsurface damage depth and surface roughness can be used to achieve rapid, accurate, and non-destructive detection of the depth of subsurface damage and provides technical guidance for subsequent grinding and polishing processes. [ABSTRACT FROM AUTHOR]

Planar partial coalescence is a phenomenon in which a droplet at a free surface or interface between two fluids coalesces into the plane surface producing a smaller droplet rather than coalescing completely. This smaller, 'daughter' droplet will be driven towards the interface by gravity and capillary forces resulting in a cascade effect of progressively small daughter droplets until the Ohnesorge Number approaches ~1 and the cascade terminates with a full coalescence event. This paper utilizes a room temperature liquid metal alloy composed of gallium, indium and tin to study partial coalescence in a viscous quiescent medium and observed bouncing of the coalescing droplets on the interface. We observed the event using high speed videography measuring effects such as the droplet to daughter droplet ratio, droplet velocities, droplet bounce heights and coefficients of restitution for the bouncing event. An existing model (Honey & Kavehpour, Phys. Rev. E, vol. 73, 2006) from our group was used, validated and expanded upon to include buoyancy effects to estimate the initial velocity of the droplet and we developed two new models for the droplet travel and maximum bounce height. The first utilizes the Stokes model for drag to moderate success while the second utilizes a model from Beard & Pruppacher (J. Atmos. Sci., vol. 26, 1969, pp. 1066-1072) and a fourth-order Runge-Kutta numerical integration scheme to predict the droplet velocity and position as functions of time. Additionally the coefficient of restitution was determined from the model using a shooting method technique in tandem with measured data to find a coefficient of restitution value of A = 0.27 ± 0.06. This 'bouncing drop' phenomenon continues in a quiescent viscous fluid to the sub-micron scale and was facilitated by the material properties of the liquid metal including the high density, moderate viscosity and particularly high interfacial tension. [ABSTRACT FROM AUTHOR]

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Mn8Ga5 alloy has certain significance in the study of materials for magnetic refrigeration applications due to its low coercivity. In this paper, the structure, magnetic properties and magnetocaloric effects (MCE) of Mn8−xCrxGa5 (x = 1.3, 1.7) polycrystalline alloys were first studied by using X-ray diffraction (XRD) technique, scanning electron microscope (SEM), energy-dispersion (EDS) analysis and magnetization measurement. The two samples crystallized in a cubic (Zn8Cu5)-type structure with space group of I-43 m (No. 217). The lattice constants and crystallite sizes of Mn8−xCrxGa5 increase with the increase of Cr concentration. As the Cr content increases, the Curie temperature (Tc) of Mn8−xCrxGa5 (x = 1.3, 1.7) is increased from 145 to 187 K. The saturation magnetic moments of Mn8−xCrxGa5 are 33.8 (x = 1.3) and 36.6 (x = 1.7) emu/g under the magnetic field of 16 kOe at 80 K, respectively. A second-order magnetic phase transition occurred in Mn8−xCrxGa5 alloy samples. The maximum magnetic entropy changes (|∆SM|) of Mn8−xCrxGa5 are 0.9 (x = 1.3) and 0.8 J·kg−1·K−1 (x = 1.7), and the relative cooling power (RCP) values are 25 (x = 1.3) and 17 J/kg (x = 1.7) under 15 kOe magnetic field. [ABSTRACT FROM AUTHOR]