Construction Of Devices Research Articles

Mass Transport and Energy Conversion of Magnetic Nanofluids from Nanoparticles’ Movement and Liquid Manipulation

Magnetic nanofluids, also referred to as ferromagnetic particle levitation systems, are materials with highly responsive magnetic properties. Due to their magnetic responsiveness, excellent controllability, favorable thermal characteristics, and versatility, magnetic nanofluids have sparked considerable interest in both industrial manufacturing and scientific research. Magnetic nanofluids have been used and developed in diverse areas such as materials science, physics, chemistry and engineering due to their remarkable characteristics such as rapid magnetic reaction, elastic flow capacities, and tunable thermal and optical properties. This paper provides a full and in-depth introduction to the diverse uses of ferrofluids including material fabrication, fluid droplet manipulation, and biomedicine for the power and machinery sectors. As a result, magnetic nanofluids have shown promising applications and have provided innovative ideas for multidisciplinary research in biology, chemistry, physics and materials science. This paper also presents an overview of the device construction and the latest developments in magnetic-nanofluid-related equipment, as well as possible challenging issues and promising future scenarios.

Precipitation of oxide dispersion strength steels after long-term annealing at temperature of 475 °C

Oxide dispersion strengthened steels are key alloys used in nuclear installations. Steels with chromium content of up to 10 wt % are suitable due to their advantageous properties and these alloys are used for the construction of technological devices in the primary circuit of nuclear power plants. From other studies, it can be concluded that chromium has anti-corrosive properties due to the formation of a passivation layer, which results in reduced activation of the material by thermal neutrons. Macroscopic properties are determined by their microstructure, and therefore, the description of the microstructure is important. Transmission Mössbauer spectroscopy and atom probe tomography were used to characterise the material. This provides information about the physical and/or chemical environment of the resonant atoms can be obtained. Obtained spectral parameters reach saturation values from which the solubility limit of chromium in iron can be determined. In Cr-rich phase, the solubility limit can be estimated from the value of spectral parameters of the single-line in the spectrum annealed for the longest time. The suggested procedures are subsequently applied to the case studies of stainless steels suitable for the construction of various components of the III+/IVth generation of nuclear reactors (including fast and fusion reactors).

A Design and Construction of the Vibration Perception Threshold Measurement Device for Diabetes

The purpose of this study was to design and build a mechanical vibration assessment tool for diabetic patients’ peripheral nervous systems. There is a substantial correlation between peripheral sensory neuropathy and vibration perception threshold (VPT). Peripheral sensory neuropathy has been identified by VPT determination utilizing the VPT measurement instrument built for that purpose. The designed device can assist in determining the threshold and tracking any progressive changes or trends. This designed device consists of two main components: hardware and software. The hardware part includes a DC power supply circuit, an Arduino NANO, a display, an isolation MOSFET driver for the electrical isolation circuit, a transducer driver, and a transducer head. The software part uses C programming on the Arduino to generate signals and display the transducer supply voltage. The testing results consist of 1) the voltage settings results (5–30 volts) comparing the voltage values on the display between the designed device and a digital multimeter, which has an average error of 0.75%, 2) According to the transducer head pressing test results, the Vibrotest Digital Biothesiometer and the proposed device had different pressing weights of ±0.02 g, and 3) the electrical safety testing results of the designed device is in the standard of IEC60601-1. (IEC: International Electrotechnical Commission).

High Performance As-Cast Organic Solar Cells Enabled by a Refined Double-Fibril Network Morphology and Improved Dielectric Constant of Active Layer.

High performance organic solar cells (OSCs) are usually realized by using post-treatment and/or additive, which can induce the formation of metastable morphology, leading to unfavorable device stability. In terms of the industrial production, the development of high efficiency as-cast OSCs is crucially important, but it remains a great challenge to obtain appropriate active layer morphology and high power conversion efficiency (PCE). Here, efficient as-cast OSCs are constructed via introducing a new polymer acceptor PY-TPT with a high dielectric constant into the D18:L8-BO blend to form a double-fibril network morphology. Besides, the incorporation of PY-TPT enables an enhanced dielectric constant and lower exciton binding energy of active layer. Therefore, efficient exciton dissociation and charge transport are realized in D18:L8-BO:PY-TPT-based device, affording a record-high PCE of 18.60% and excellent photostability in absence of post-treatment. Moreover, green solvent-processed devices, thick-film (300nm) devices, and module (16.60 cm2) are fabricated, which show PCEs of 17.45%, 17.54%, and 13.84%, respectively. This work brings new insight into the construction of efficient as-cast devices, pushing forward the practical application of OSCs.

Chiral dual-core emitters based-on through-space coupling for high-performance OLEDs with little efficiency roll-off

Through-space coupling (TSC) is the essential component of π-stacked systems and has promise in charge transport and electronic communication, which is of great significance for the construction of efficient and stable photoelectric devices. In this work, we demonstrate a chiral dual-core strategy for the design of high-performance organic circularly polarized emitters, which features of connecting two thermally activated delayed fluorescence (TADF) luminophores with chiral linkage that allows efficient TSC to occur. Using this strategy, a pair of dual-core enantiomers, R/S-DNKP, were designed and synthesized by linking two benzophenone derivatives with a 1,1′-bi-2-naphthol unit. Compared to the mono-core counterpart NKP, the dual-core emitters exhibited the photoluminescence quantum yields up to 94 %. Moreover, benefiting from their chiral helical folding configurations, the R/S-DNKP enantiomers exhibited the luminescence dissymmetry factor (|glum|) value of +2.7 × 10−3 and −2.6 × 10−3 in doped films. Notably, the electroluminescence devices based on the R/S-DNKP enantiomers achieved external quantum efficiency values of 21.5 % and 19.7 % with little roll-off. It is believed that this molecular design strategy will pave new routes for the development of high-performance chiral emitters for future organic photonic devices.

Magnetic Bistability in the Crystaline Fullerene Radical Salt

Comprehensive SummaryCompounds with magnetic bistability is highly attractive for the construction of switches, thermal sensors, information‐storage media and memory devices. Herein, we report a crystalline fullerene radical anion salt [Na(THF)5]C60 (1), obtained by the reduction of C60 with Na in solution, which exhibits magnetic bistability accompanied with one magnetostructural transition, giving low temperature (LT), high temperature (HT) phases and a metastable phase. Fullerene radical anions (C60•‐) in the structure were found arranged into a three‐dimensional close‐packed honeycomb subnetwork with hollow channels occupied by complex cations [Na(THF)5]+ as spacers. The magnetic bistability is attributed to structural transitions as the LT−IT phase transition was associated with the orientational disorder of fullerene anions and the distortion of the complex cations [Na(THF)5]+ in the 3D packing of fullerene anions.

The construction of a flexible solid-state asymmetric supercapacitor device using nickel-copper oxide nanoplates and carbon nanosphere serving as positive and negative electrode, respectively with excellent electrochemical capabilities

Here, nickel-copper oxide nanoplates (NCN) and carbon nanosphere (CNS) as positive and negative electrodes are synthesised via a hydrothermal protocol without adding any surfactant and binders. The NCN and CNS electrodes in KOH electrolyte exhibit superior specific capacitance of ∼ 2362.5 F g−1 and ∼ 246.11 F g−1 at 1 A g−1 respectively. The NCN and CNS retained 98.54 % and 97.88 % of the initial capacitance after 3000 galvanostatic charge–discharge (GCD) cycles, respectively. Additionally, an asymmetric supercapacitor (ASC) device NCN//CNS is constructed using NCN and CNS as positive and negative electrodes, utilizing poly(vinyl alcohol) PVA − KOH gel electrolyte separator. The ASC device demonstrates a maximum energy density of 50.4 Wh kg−1 (181.44 KJ kg−1) with a power density ∼ 750 W kg−1 at 1 A g−1, maintaining 90.4 % cyclic stability after 10,000 GCD cycles. The electrochemical outputs of the device present significant potential for the advancement of high-performance ASC devices in electronic applications.

Development of a capillary temperature control system for capillary electrophoresis instruments designed for spaceflight applications.

Capillary temperature control during capillary electrophoresis (CE) separations is key for achieving accurate and reproducible results with a broad array of potential methods. However, the difficulty of enabling typical fluid temperature control loops on portable instruments has meant that active capillary temperature control of in situ CE systems has frequently been overlooked. This work describes construction and test of a solid-state device for capillary temperature control that is suitable for inclusion with in situ instruments, including those designed for space missions. Two test articles were built, a thermal mass model (TMM) and a functional model (FM). The TMM demonstrated that temperature gradients could be limited using the proposed control scheme, and that our thermal modeling of the system can be relied on for future adaptations of physical geometries of the system. The FM demonstrated CE analytical performance while under active temperature control and that the device was compatible with the harsh thermal-vacuum environments that might be encountered during space flight.

Facile synthesis of flower-like NiCo/NiO–CoO surrounded by N-doped porous carbon derived from covalent organic framework for aqueous asymmetric supercapacitor

The persisting quest for improving charge density, electronic conductivity and cyclic stability of the electrode material in supercapacitor (SC) applications still demands intensive research and advancements. This study also aims the aforementioned pursuit with the construction of hybrid supercapacitor using mixed metal oxides with the incorporation of metal and supported with porous carbon to improve the charge density, electrical conductivity and cyclic stability, respectively. A covalent organic framework (COF) was synthesized and doped with nickel (Ni2+) and cobalt (Co2+) ions followed by carbonization at 1000 °C for 3 h to generate NiCo/NiO–CoO surrounded N-doped porous carbon (NPC) framework. The X-ray diffraction reveals that nickel considerably impacts the crystallinity of NiCo/NiO–CoO and the Raman spectroscopy revealed that the NiCo/NiO-CoO-NPC with an equal molar ratio of Ni2+ and Co2+ ions (NiCo/NiO-CoO-NPC-2) offered the highest degree of graphitization. The electron microscopic images showed the formation of flower-like morphology of NiCo/NiO-CoO-NPC-2 with a size of 250 nm and the greater number of flowers on NPC's surface could augment the electrochemical activity of the composite material. The NiCo/NiO–CoO-NPC-2 offered an attractive specific capacitance (Cs) of 845 F g−1 @ 1 A g−1 and preserves 93% capacity retention @ 10 A g−1 after 6000 charge-discharge cycles while exploited in SC application. The metal-free COF carbonized at 900 °C (CCOF-900) is utilized as the negative electrode with a Cs of 286 F g−1 @ 1 A g−1 for the construction of an asymmetric supercapacitor device and the NiCo/NiO-CoO-NPC-2//CCOF-900 device delivered efficient energy of 54 Wh kg−1 at a power density of 633 W kg−1.

A solar battery containing functional metal electrodes

Solar battery is a device that simultaneously converts and stores solar energy. In most of the cases, conversion of solar energy is achieved by means of a photoelectrode while electric energy is stored through oxidation and reduction of appropriate redox electrolytes. In the present work, a modified version of a solar battery is presented by introducing simple metal electrodes without any electrocatalysts. Thus a Zn foil plays the role of cathode during photocharging and the role of anode during battery discharging while a copper or a silver foil plays the role of cathode during discharging. The proposed design leads to the construction of a multifunctional device which provides photocharging, battery operation and a quantum-dot-sensitized solar cell functionality.

Rational design of diamond through microstructure engineering: From synthesis to applications

AbstractDiamond possesses excellent thermal conductivity and tunable bandgap. Currently, the high‐pressure, high‐temperature, and chemical vapor deposition methods are the most promising strategies for the commercial‐scale production of synthetic diamond. Although diamond has been extensively employed in jewelry and cutting/grinding tasks, the realization of its high‐end applications through microstructure engineering has long been sought. Herein, we discuss the microstructures encountered in diamond and further concentrate on cutting‐edge investigations utilizing electron microscopy techniques to illuminate the transition mechanism between graphite and diamond during the synthesis and device constructions. The impacts of distinct microstructures on the electrical applications of diamond, especially the photoelectrical, electrical, and thermal properties, are elaborated. The recently reported elastic and plastic deformations revealed through in situ microscopy techniques are also summarized. Finally, the limitations, perspectives, and corresponding solutions are proposed.

Interfacial second harmonic generation switching with 2D monolayer/VO2 heterostructure

To establish a facile nonlinear optical switching mechanism activated by thermal field, that is compatible with on-chip integration, we develop a physical model to quantify the interfacial second harmonic generation (SHG) of 2D monolayer/3D phase-changing material heterostructure. Our results show that heat-induced phase transition of VO2 can realize temperature-reversible interfacial SHG switching, with an ON-OFF ratio of about 3 and a low temperature threshold of about 60 °C. Experimental results can be well addressed by quantitative calculations based on the physical model. This work constitutes substantial insights into interfacial SHG switching, which will benefit design and construction of on-chip nonlinear optical devices based on 2D monolayers.

Intelligent Tribotronic Transistors Toward Tactile Near‐Sensor Computing

AbstractFor the next generation of human‐machine interaction (HMI) systems, the development of a tactile interaction unit with multimodal, high sensitivity, and real‐time perception and recognition is the key. Herein, an artificial tactile near‐sensor computing (ATNSC) unit based on a triboelectric tactile sensor and an organic synaptic transistor is reported. By introducing multi‐peak microstructures, the mechanical performance of the tactile sensor is optimized, showing a high sensitivity of 0.98 V kPa−1 in the pressure range of 0–10 kPa and maintaining 0.11 V kPa−1 at high pressures up to 350 kPa. Additionally, by designing stripe‐like convex structures on the top surface, the sensor is capable of bimodal perception in both pressure and sliding sensations. Furthermore, the organic synaptic transistor, which can be driven by tactile sensing stimuli in a variety of circumstances, is achieved utilizing an ion‐rich gelatin dielectric covered by a hydrophobic polymer coating layer. The ATNSC unit well demonstrates the stimuli‐dependent short‐term memory effect, and it enables tactile near‐sensor computing for feature action recognition in an HMI system, laying a solid foundation for the construction of intelligent interaction devices.

Creation and Construction of a Multifunctional Agricultural Device

The microprocessor is responsible for coordinating the actions of actuators, such as pumps and motors, in order to gently cover the seeds with soil and supply the required moisture and nutrients for germination. The device also has an adjustable spray mechanism that may be used to dispense water and nutrients according to the crop's and soil's unique requirements. The Smart Seed Sowing System reduces resource waste and supports environmental sustainability while increasing production and efficiency via the smooth integration of hardware and software. Furthermore, it may be used in a variety of agricultural contexts, from tiny family farms to expansive commercial enterprises, because to its scalability and interoperability. The Smart Seed Sowing System is a promising tool as we approach a new agricultural revolution that will be marked by innovation and automation. The system's precision agricultural methods guarantee precise seed planting, even soil covering, and focused fertilizer administration, which leads to healthier plants, less of an adverse effect on the environment, and increased sustainability. All things considered, the Smart Seed Sowing System has enormous potential to advance development and prosperity in the agricultural industry, while promoting sustainability and global food security for coming generations.

Manipulation of high-frequency spin waves in ferromagnetic thin films via magnetic torques induced by ultrafast demagnetization

Spin-based technologies demand the effective excitation and control of high-frequency spin waves in order to increase the operational speed of magnonic logic circuits. An available option for the high-frequency spin wave is the perpendicular standing spin waves (PSSWs) in ferromagnetic thin films. However, the practical utilization of a PSSW is still challenging due to a few unsolved critical issues such as its relatively low amplitude and simultaneous excitation of other PSSW modes. Here, efficient excitation and control of a first-order PSSW mode are demonstrated in Ni80Fe20 thin films using a double-laser-pulse scheme. Based upon our experimental and theoretical investigations, it is found that the precession amplitudes of the Kittel and PSSW modes show strong dependence on equivalent torques (i.e., the averaged torques during fast relaxation process after the second pulse excitation) applied to these two modes. Thus, selective excitation and amplification of the first-order PSSW mode can be realized by manipulating the equivalent torque, i.e., introducing a second laser pulse with an appropriate arrival time and laser fluence. Moreover, the spectral tuning of this single PSSW mode can be achieved by proportionately adjusting the laser fluence of two pump pulses. These findings may pave the way for the realization and construction of future high-performance spintronic devices.

Long-range air-host plasmonic propagation with subwavelength confinement

Confining light at a subwavelength scale is important for building ultracompact opto-electronic networks. Plasmonic waveguides are good candidate devices for this purpose. However, the oscillation of electrons relating to surface plasmon polaritons causes energy dissipation, which limits the propagation length and thus reduces the waveguide performance. Here, we design a low-loss plasmonic waveguide composed of a nanowire dimer structure on a metal substrate, in which the dominant modes are localized within the air gap between the nanowires and referred to as air-host plasmonic modes. The use of air instead of dielectric materials as the host medium can reduce ohmic loss and avoid the dispersion effect of dielectric. When the constructed nanowires have a diameter less than 100 nm, the air-host mode has subwavelength-scale confinement and a propagation length of ∼100 μm, which has broad application prospects for the construction of ultracompact plasmonic devices.

Analysis and Basics of Improving the Process of Cutting Electrical Sheet Bundles with a High-Pressure Abrasive Water Jet.

Electrical steels are widely used in the electrical industry in the construction of many devices, e.g., power transformer cores and distribution transformers. An important parameter of electrical components that determines the efficiency of devices is energy loss during remagnetization. These losses are influenced, among other factors, by steel cutting processes. The common techniques for cutting electrical materials on industrial lines are mechanical cutting and laser cutting. High-pressure abrasive water jet (AWJ) cutting, unlike the technologies mentioned above, can ensure higher quality of the cut edge and limit the negative impact of the cutting process on the magnetic properties of sheet metal. However, the correct control of the process and the conditions of its implementation comprise a complex issue and require extensive scientific research. This work presents a new approach to cutting electric sheets, involving bundle cutting, which significantly increases the processing efficiency and the dimensional and shape accuracy of the cut details. The tests were carried out for bundles composed of a maximum of 30 sheets, ready to be joined in a stator and rotor in a motor. The influence of processing conditions on the quality of the cut edges of sheet metal, the width of the deformation zone, and the burr height were analyzed. The detailed analysis of the quality of the cut edges of electrical bundled sheets creates new possibilities for controlling the AWJ cutting process in order to obtain a product with the desired functional and operational properties.

Synergic enhancement of hydrogel upon multi-level hydrogen bonds via macromolecular design for dual-mode electronic skin

Acrylamide (AM) derivative polymer hydrogels were widely used due to their excellent mechanical performances and the ease to be further functionalized, while there are significant differences in both microstructure and performances along with the variation of substituent groups. So far, the intrinsic reason for this is never revealed. In this paper, double network hydrogels with three AM derivative monomers as the first polymer network: AM, N,N-dimethylacrylamide (DMAA) and N-hydroxymethylacrylamide (NMA), and methyl cellulose (MC) as the second network, were prepared. Compared with PAM based hydrogel, the elasticity and toughness of PDMAA based hydrogel increased by two times. The results from molecular dynamics simulation, FT-IR and XRD demonstrate that intermolecular force among polymer networks in hydrogels increased with AM derivative polymers achieved from primary amine to tertiary amine (DMAA), stemmed from the variation of substituent groups on N atom of AM derivative monomers. The PDMAA based hydrogel was finally employed to construct a dual-mode electronic skin, in a wearable sensor with the fastest response of 0.1 s and a self-powered device with a capacitance of 438.27 mF/cm2. This work provided an in-depth understanding for the optimization of PAM based hydrogels and a novel way for the construction of flexible devices.

Rational design of natural leather-based water evaporator for electricity generation and functional applications

In recent years, water evaporation-induced electricity has attracted a great deal of attention as an emerging green and renewable energy harvesting technology. Although abundant materials have been developed to fabricate hydrovoltaic devices, the limitations of high costs, inconvenient storage and transport, low environmental benefits, and unadaptable shape have restricted their wide applications. Here, an electricity generator driven by water evaporation has been engineered based on natural biomass leather with inherent properties of good moisture permeability, excellent wettability, physicochemical stability, flexibility, and biocompatibility. Including numerous nano/microchannels together with rich oxygen-bearing functional groups, the natural leather-based water evaporator, LeatherEmblic-NPs-SA/CB, could continuously produce electricity even staying outside, achieving a maximum output voltage of ∼3 V with six-series connection. Furthermore, the leather-based water evaporator has enormous potential for use as a flexible self-powered electronic floor and seawater demineralizer due to its sensitive pressure sensing ability as well as its excellent photothermal conversion efficiency (96.3%) and thus fast water evaporation rate (2.65 kg m−2 h−1). This work offers a new and functional material for the construction of hydrovoltaic devices to harvest the sustained green energy from water evaporation in arbitrary ambient environments, which shows great promise in their widespread applications.

Microstructural and Current-voltage Characteristics in Mo/HfO2/n‑Si Based Metal-Insulator-Semiconductor (MIS) Diode using Different Methods for Optoelectronic Device Applications

This paper investigates the effect of hafnium dioxide (HfO2) thin film as interlayer between the Mo and n-Si semiconductor on the electrical characteristics of the Mo/n-Si Schottky diode (SD). The X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) results confirmed that HfO2 films were formed on the n-Si semiconductors. The image from SEM and AFM displays that the deposited HfO2 thin film had a uniform appearance good smoothness of the surface. The smooth surfaces of the insulating layer strongly influence the electrical properties of the diode. The electrical properties of the Mo/HfO2/n-Si metal/insulator/semiconductor (MIS) diode were obtained via current-voltage (I-V) measurements in the voltage range from −3 V to +3 V at room temperature. A better rectifying ability and a reduced reverse leakage current were demonstrated by the MIS diode. The MIS dide's barrier height (Bh) and ideality factor value were calculated to be 0.85 eV and 1.21, respectively. The MIS diode was able to achieve a higher b, which allowed the HfO2 interlayer to change BH. The calculated BH values from the I-V, Hernandez, Cheung, and Norde approaches were comparable to one another, demonstrating their validity and consistency. The MIS diode's forward bias log (I) - log (V) curve demonstrated that it was ohmic in low-voltage regimes and that conduction was space-charge-limited in high-voltage regimes. However, for the MIS diode, the Poole-Frenkel and Schottky emissions are the dominant current conduction mechanisms in the lower and higher bias regions. These outcomes indicate that the HfO2 film can be chosen as dielectric materials in the construction of MIS devices.