Uniform Characteristics Research Articles

First Report of Leaf Spot Caused by Paramyrothecium foliicola on Peanut in China.

Peanut (Arachis hypogaea) is an important economic and oil crop in China. In September 2022, leaf spots wereobserved on peanut in Luoyang city, Henan province, China (34°49'N, 112°37'E). The disease occurred on about 30% ofthe peanutleaves in only one 0.5-acre field. Symptoms appeared primarily as brown spots, that varied in shape, and appeared round, oval or irregular. In addition, some disease patches exhibited a concentric ring pattern. Small pieces (5×5 mm) of five diseased leaves were surface disinfected in 3% NaClO for 2 minutes, rinsed three times in sterile distilled water, dried on sterilized filter paper, and cultured on potato dextrose agar (PDA) at 25°C for 3 days. Five isolates with uniform characteristics were obtained and subcultured by transferring hyphal tips to fresh PDA. The colonies of the isolates were circular and the margins were clean. The colonies showed white coloration, and after 5-7 days of incubation on PDA plates, concentric rings with dark green sporodochia appeared on the surface of the colonies. The conidiophores branched repeatedly. The conidiophore stipes unbranched, hyaline, 10.0 to 23.2×1.5 to 3.3 μm (n=50). The conidia were rod-shaped or long oval and single-celled, measuring 4.6 to 8.6×1.4 to 3.1 μm (n=100). Based on these characteristics, the five isolates were identified as Paramyrothecium foliicola (Lombard et al 2016). Genomic DNA was extracted from the representative isolates LH-1-1 and LH-1-2. The internal transcribed spacer (ITS), RNA polymerase II second largest subunit (RPB2), calmodulin (CmdA), and translation elongation factor 1-alpha (tef1) loci were amplified and sequenced using the following primer pairs: ITS1/ITS4 (White et al. 1990), RPB2-5F2/RPB2-7cR (O'Donnell et al. 2007), CAL-228F/CAL-2Rd (Carbone & Kohn 1999), and EF1-728F/EF2 (O'Donnell et al. 1998), respectively. BLASTn analysis revealed that the sequences of ITS (OR352397.1 and OR417392.1), RPB2 (OR413573.1 and OR420678.1), CmdA (OR413572.1 and OR420677.1), and tef1 (OR413574.1 and OR420679.1) had 99 to 100% (553/558 bp, 721/721 bp, 597/598 bp, and 384/389 bp) similarity to P. foliicola (MN593634.1, MN398038.1, OM801785.1, MK335967.1). A phylogenetic tree based on the Maximum Likelihood method also confirmed that the two isolates converge on the same branch as P. foliicola. Pathogenicity tests were performed using leaves of 60-day-old peanut plants (cv. Zhonghua 8). Briefly, uninfected healthy leaves (non-wounded) were inoculated with 30-µl drops containing a spore suspension (5×105 conidia/ml) of LH-1-2, and peanut leaves inoculated with sterile distilled water served as controls. All treatments were incubated in an incubator at 25℃ and high relative humidity with a 12:12 hour light-dark cycle. After 5-7 days, inoculated leaves showed symptoms similar to those observed in the field, while no symptoms were observed on control leaves. The pathogenicity tests were repeated three times. The fungus was reisolated from the infected leaves and identified as P. foliicola based on morphological and molecular characteristics, thus fulfilling Koch's postulates. P. foliicola has previously been reported to cause leaf spot of tomato and mung bean, stem canker of cucumber (Huo et al. 2022; Sun et al.2020; Huo et al. 2021). To our knowledge, this is the first report of P. foliicola causing leaf spot on peanut in the world. Identification of this pathogen will be helpful in monitoring peanut diseases and developing disease control strategies.

Three-Dimensional-Printed Sodium Alginate and k-Carrageenan-Based Scaffolds with Potential Biomedical Applications.

This work reports the development of a marine-derived polysaccharide formulation based on k-Carrageenan and sodium alginate in order to produce a novel scaffold for engineering applications. The viscoelastic properties of the bicomponent inks were assessed via rheological tests prior to 3D printing. Compositions with different weight ratios between the two polymers, without any crosslinker, were subjected to 3D printing for the first time, to the best of our knowledge, and the fabrication parameters were optimized to ensure a controlled architecture. Crosslinking of the 3D-printed scaffolds was performed in the presence of a chloride mixture (CaCl2:KCl = 1:1; v/v) of different concentrations. The efficiency of the crosslinking protocol was evaluated in terms of swelling behavior and mechanical properties. The swelling behavior indicated a decrease in the swelling degree when the concentration of the crosslinking agent was increased. These results are consistent with the nanoindentation measurements and the results of the macro-scale tests. Moreover, morphology analysis was also used to determine the pore size of the samples upon freeze-drying and the uniformity and micro-architectural characteristics of the scaffolds. Overall, the registered results indicated that the bicomponent ink, Alg/kCG = 1:1 may exhibit potential for tissue-engineering applications.

Comprehensive Physical Characterization of Silver Nanoparticles: Multimodal Evaluation of Material Properties

This study investigates the characterization of silver nanoparticles (AgNPs) through a variety of analytical techniques to evaluate their physical properties and potential applications. Particle size analysis, utilizing Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM), consistently showed an average diameter of approximately 20-30 nanometers. Surface area assessments, conducted via BET analysis and gas adsorption, revealed a surface area ranging from 32 to 48 m²/g, indicating the nanoparticles’ applicability across various fields. Composition analysis using Energy-Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), and Atomic Force Microscopy (AFM) confirmed that the AgNPs comprised 84-94% silver content, supporting their crystalline structure. Optical properties evaluated through UV-Vis spectroscopy demonstrated stable absorption peaks between 410 and 440 nanometers, with plasmon resonance values from 2.82 to 3.24 electron volts (eV). Despite slight variations in light reflectivity, the uniform optical characteristics across samples suggest consistent behavior. Overall, this comprehensive characterization enhances the understanding of AgNPs, underscoring their potential in nanotechnology, biomedicine, and environmental applications.

Study of Sediment Deposit Characteristics based on Geotechnical Properties and Geographic Information System (GIS) Approaches

Several sedimentation processes occur in the downstream area between river mouths and the sea. One of the effects of this sedimentation process is the occurrence of siltation around the coast. Not infrequently, this disrupts sea passages when the ship is about to head to the pier or go to sea. Kuala Beach is one of the locations in Pangkalpinang where the sedimentation process continues to occur enough to disrupt the smooth flow of sea traffic. This study aims to provide an overview and analysis of results related to sediment characteristics, spatial analysis of deposits, and predictions of deposition rates around Kuala Beach, Pangkalpinang City. This research was conducted using the following methods: 1) Method of investigating sediment characteristics by collecting data through field testing in the form of hand drills and laboratory testing, 2) Spatial analysis method by mapping the area of sedimentation based on the results of sediment characteristic tests using Agisoft Metashape and QGIS. The results of this study note that sediment deposits are dominated by sediments with sandy grain characteristics (SP symbol based on the Unified Soil Classification System) and a fine grain content (passing sieve number 200) of around 1-3%. The pattern of distribution of sediment deposits is known to have relatively flat contours and relatively uniform characteristics down to a depth of 1.5 m. The coefficient of grain uniformity (Cu) is in the range of 2.43-8.2 with the tendency of uniformity level getting higher to the southeast. The coefficient of grain gradation (Cc) is in the range of 0.44-1.64 with the tendency of the gradation level getting better to the southeast.

Performance evaluation of a novel monofilar helical antenna with tapered cross-section wire fabricated via metal additive manufacturing

This paper presents a novel formulation for a generalized helical antenna that incorporates non-uniform helix diameters, non-uniform helix spacing, and non-uniform wire cross-section, providing additional degrees of freedom for optimization. By carefully defining the transition between the helix and the center feed point, a thicker wire was used at the base to enhance the antenna’s operating bandwidth capability and mechanical strength, eliminating the need for additional support structures. The fabrication process utilized metal additive manufacturing (MAM) with Maraging steel. The results demonstrate that the helical antenna with a tapered cross-section wire (with a thicker base and a thinner tip) exhibits significantly better performance compared to the control models for operation in the X-band. This design amalgamates impedance matching from antennas with uniform thick wires and radiation characteristics from antennas with uniform thin wires. The major contribution of this work is the demonstration that employing tapered wire cross-sections can enhance helical antenna performance, thereby introducing a new design parameter in metal additive manufacturing. Specifically, we present an eight-turn helical antenna that achieved a measured reflection coefficient less than −10 dB and axial ratio less than 1 dB over the X band, with a peak realized gain in RHCP of 10.8 dBic.

Effect of Surface Pretreatment to Reduce the Incubation Period of Iridium Thin Films Grown by ALD on the Oxide Surface

Iridium (Ir) has low figure of merit(×λ) and high melting temperature properties, so it has been recently spotlighted as a very important copper (Cu) alternative interconnect material in next-generation semiconductor devices. In particular, in the case of depositing a thin film using atomic layer deposition (ALD) technology, it can be expected to deposit extremely thin film with conformal, uniform and excellent step coverage characteristics even in a very complex structure or a trench structure of several nm dimension due to the inherent self-limiting characteristic of ALD. In this regard, ALD-Ir is considered as one of the most suitable metallization process for the application of advanced semiconductor interconnects. Therefore, considerable efforts have been conducted to develop a reliable ALD-Ir process having improved film qualities. And, ALD-Ir process with excellent thin film properties such as low electrical resistivity and negligible oxygen impurities was recently reported using Tricarbonyl (1,2,3-η)-1,2,3-tri(tert-butyl)-cyclopropenyl iridium (C18H27IrO3 or TICP) precursor and oxygen [1]. However, in the case of this TICP precursor, it was difficult to deposit extremely thin and continuous Ir films on the hydroxyl-terminated oxide layer due to its long incubation delay.Therefore, in this study, a method for depositing a very thin, uniform and continuous ALD-Ir thin film with low resistivity even on oxide materials was explored by reducing the incubation period and promoting nucleation using various surface pretreatment conditions. In addition, the nucleation behavior as well as film properties of ALD-Ir on the oxide material were systemically compared and analyzed according to the surface pretreatment conditions, and finally, ALD-Ir thin film with excellent properties on the oxide surface was obtained.

Effect and simulation of tensile stress on corrosion behavior of 7050 aluminum alloy in a simulated harsh marine environment

The corrosion behavior of the 7050 aluminum alloy was investigated in the presence of high concentrations of H+ and Cl- ions simulating the marine environment of high salinity and local acidification in tropical seas. The results highlight the significant influence of tensile stress on the corrosion rate of the aluminum alloy with higher stress levels resulting in faster corrosion. Under the influence of tensile stress, corrosion pits form on the alloy surface, and their depth increases with higher levels of applied stress. It is important to note that the presence of a corrosion defect leads to a pronounced stress concentration, resulting in a much faster rate of corrosion compared to other regions. However, when subjected to low tensile stress (≤174 MPa), the corrosion at the defect exhibits uniform characteristics similar to a uniform corrosion process. Moreover, the potential at the defect shifts positively with increasing stress level. Furthermore, stress has an effect on the diffusive behavior of the aluminum alloy, leading to a higher potential at the defect center compared to its surrounding region. Nevertheless, as the tensile stress is further increased, this behavior is disrupted and stress corrosion cracking becomes the dominant mode of corrosion.

Effect analysis on the flow uniformity and pressure drop characteristics of the rotary diesel particulate filter for heavy-duty truck

In this work, a three-dimensional simulation model and mathematical models of the rotary diesel particulate filters (R-DPF) for heavy-duty truck was established to investigate its velocity and total pressure distribution characteristics. The effect mechanism of the particle load, particle volume fraction, inlet velocity, porosity and micropore diameter on the flow uniformity and pressure drop characteristics of the R-DPF under different conditions were obtained through the simulation. The results indicate that the change in the airflow direction and the osmotic resistance from the filter material are the main reasons for the flow uniformity and pressure drop characteristics of the R-DPF for heavy-duty truck. The R-DPF with higher particle load or inlet velocity has better flow uniformity. Whereas the R-DPF with higher particle volume fraction has worse flow uniformity. The increase in the porosity and micropore diameter make the flow uniformity of the R-DPF show a trend of decreasing first and then increasing. Besides, the increase of the particle load, particle volume fraction and inlet velocity will enlarge the total pressure drop of the R-DPF, while the increase of the porosity and micropore diameter will lower the total pressure drop of the R-DPF.

Exploration of B and T Cell Receptor Repertoires Reveals Distinct Mechanisms in Pure Red Cell Aplasia, Autoimmune Hemolytic Anemia, and Aplastic Anemia

Background: Pure red cell aplasia (PRCA), autoimmune hemolytic anemia (AIHA) and aplastic anemia (AA) are immune-mediated diseases that mainly attack erythrocyte or erythroid progenitor cells. This study aimed to investigate changes related to autoimmunity in the B cell receptor (BCR) and T cell receptor (TCR) repertoires in these diseases. Methods: Patients with newly diagnosed primary PRCA, AIHA, and AA and healthy individuals with matched age and sex (normal controls, NC) were recruited. Peripheral blood was collected, and BCR and TCR repertoires were sequenced by next-generation immunosequencing. The diversity and clonal expansion of the repertoires, gene and gene combination usage, somatic hypermutation (SHM) of BCR, and the sequence length, hydrophobicity, motifs of the most diverse epitope encoded (complementary-determining region 3, CDR3), T cell clustering, and BCR light chain and TCRα chain were analyzed. Results: 10 PRCA, 10 AIHA, 10 AA, and 7 NC were finally enrolled. For the broad repertoire metrics analysis, only the TCR repertoire of the AA group was more diverse compared with NC (p＜0.05). For BCR and TCR repertoires, PRCA, AIHA, and AA showed uniform characteristics in gene usage. The preferential gene usage of PRCA immunoglobulin heavy (IGH) chains such as IGHV3-23, IGHV3-74 were correlated with memory cells and red blood cell antigen recognition; the higher usage of IGHV4-31 in the AIHA group was associated with secretion of auto-antibodies; whereas AA patients had more gene usage of neutralizing antibodies (p＜0.05). In the gene usage in T cell receptor β (TRB) chains, PRCA patients had skewed usage of genes associated with T cell dysregulation and hyperinflammation such as TRBV1 and TRBV11-2; the increased gene usage in AIHA and AA were also found in other autoimmune diseases, which correlated with abnormal antigen recognition. PRCA and AA also had specific TRBV-J gene combination usage. Only PRCA had higher BCR SHM compared with NC (p＜0.05). The length of CDR3 was similar but the hydrophobicity was different among different disease groups. 12, 28, and 22 motifs were found respectively in BCR of PRCA, AIHA, and AA; and 13, 6, and 6 motifs were found in TCR. Compared with NC, PRCA, AIHA, and AA showed a considerable lack of physiology T cell clusters, and 147, 98, and 141 disease-specific T cell clusters in each disease was found, respectively. For light chain of BCR, PRCA and AIHA had the tendency of more usage of κ chains, whereas AA had more usage of λ chains. For TCRα chains, the three diseases used more genes related to hypersensitivity reactions (p＜0.05). Conclusion: PRCA, AIHA, and AA had different BCR and TCR repertoire characteristics in gene and gene combination usage, hydrophobicity and motifs of CDR3, and T cell clustering, which might contribute to autoimmune antigen recognition. The abnormalities were mainly T cell-related for PRCA, B cell-related for AIHA and both for AA. Keywords: pure red cell aplasia; autoimmune hemolytic anemia; aplastic anemia; BCR; TCR

Density-of-state engineering of conjugated polymers by implanting partial two-dimensional conjugation: Broad absorption and high performing organic photovoltaics

Uniform and broad absorption characteristics are fundamental for improving the light-harvesting capabilities of organic photovoltaics (OPVs). A partial two-dimensional (2D) conjugated structure is formed by introducing additional conjugation in the transverse direction of the main backbone of conjugated polymers (CPs). This alters the bimodal-shaped absorption spectrum of typical donor–acceptor CPs to a trimodal-shaped profile by modulating the density of energy states, enabling uniform absorption characteristics in the visible region. The uniform and broad absorption properties of CPs can be confirmed by the proportional improvement in the short-circuit current density (JSC) and external quantum efficiency (EQE) in OPVs. In particular, when a CP with modified absorption characteristics is blended with a non-fullerene acceptor (Y6) that can absorb light in the near-infrared (NIR) region, the CP:Y6 blend exhibits a uniform light-harvesting capability from the visible to NIR regions through complementary absorption between the CP and Y6. This results in a promising power-conversion efficiency (PCE) of 16.13 % with a JSC of 27.83 mA·cm−2 and fill factor (FF) of 75.22 %. Finally, the morphological effects that determine the charge-recombination properties of the CP:Y6 blends are systematically characterized. The results confirm that the film morphology, in which small domains are uniformly formed, partly contributes to FF enhancement.

Breast intervention device for low-field MRI with a customized unilateral coil

With the incidence of breast cancer rising to the top among female malignant tumors, magnetic resonance images guided breast biopsy intervention and minimally invasive treatment have developed as a clinically practical research issue. High field studies have shown the diagnostic value of breast MRI, but the examination costs greatly exceed those of competing conventional mammography. In this case, low-field MRI cannot merely provide typical MRI contrast, but also significantly reduce the cost of diagnosis and treatment for breast cancer patients. This work describes a unilateral breast coil and prototype intervention device, which provides a customized solution for low-field MRI-guided breast intervention. Results demonstrate that the low-field MRI breast intervention device facilitates medical intervention procedures. And the designed positioning device can locate the target lesion within 2–3 mm accuracy. Phantom tests with the customized unilateral coil indicate that the open loops perform as well as the 4-channel commercial closed breast coil, presenting a relatively good SNR (signal-to-noise ratio) and uniformity characteristics. MR scanning images of the volunteer breast using the breast intervention coil also show high SNR, which lays a foundation for further implementation of image-guided breast interventional minimally invasive surgery with the low-field MRI system.

The Enhanced Performance of Neuromorphic Computing Hardware in an ITO/ZnO/HfOx/W Bilayer-Structured Memory Device.

This study discusses the potential application of ITO/ZnO/HfOx/W bilayer-structured memory devices in neuromorphic systems. These devices exhibit uniform resistive switching characteristics and demonstrate favorable endurance (>102) and stable retention (>104 s). Notably, the formation and rupture of filaments at the interface of ZnO and HfOx contribute to a higher ON/OFF ratio and improve cycle uniformity compared to RRAM devices without the HfOx layer. Additionally, the linearity of potentiation and depression responses validates their applicability in neural network pattern recognition, and spike-timing-dependent plasticity (STDP) behavior is observed. These findings collectively suggest that the ITO/ZnO/HfOx/W structure holds the potential to be a viable memory component for integration into neuromorphic systems.

Droplet freeze-thawing system based on solid surface vitrification and laser rewarming

Ultra-rapid cooling and rewarming rate is a critical technical approach to achieve ice-free cells during the freezing and melting process. A set of ultra-rapid solid surface freeze-thaw visualization system was developed based on a sapphire flim, and experiments on droplet freeze-thaw were carried out under different cryoprotectant components, volumes and laser energies. The results showed that the cooling rate of 1 μL mixed cryoprotectant [1.5 mol/L propylene glycol (PG) + 1.5 mol/L ethylene glycol (EG) + 0.5 mol/L trehalose (TRE)] could be 9.2×10 3 °C/min. The volume range of 1-8 μL droplets could be vitrified. After comparing the proportions of multiple cryoprotectants, the combination of equal proportion mixed permeability protectant and trehalose had the best vitrification freezing effect and more uniform crystallization characteristics. During the rewarming operation, the heating curve of glassy droplets containing gold nanoparticles was measured for the first time under the action of 400-1 200 W laser power, and the rewarming rate was up to the order of 10 6 °C/min. According to the droplet images of different power rewarming processes, the laser power range for ice-free rewarming with micron-level resolution was clarified to be 1 400-1 600 W. The work of this paper simultaneously realizes the ultra-high-speed temperature ramp-up, transient visual observation and temperature measurement of droplets, providing technical means for judging the ice free droplets during the freeze-thaw process. It is conducive to promoting the development of ultra-rapid freeze-thaw technology for biological cells and tissues.

Bio-inspired nanocomposite coatings on orthodontic archwires with corrosion resistant and antibacterial properties.

The corrosion resistance and antibacterial properties of fixed orthodontic devices are insufficient in the complex oral cavity, which delays tooth movement and causes enamel demineralization. To overcome the challenges, this research constructs a series of polydopamine-graphene oxide (PDA-GO) nanocoatings on representative NiTi archwires via self-assembly. The morphology, chemical structure, and multifunctional properties of coatings showed tunability dependent on the PDA/GO ratio. Optimized PDA-GO coatings with uniform and dense characteristics prolonged the diffusion path for the corrosive medium and reduced Ni dissolution in NiTi alloys. Meanwhile, the applied coatings endowed NiTi alloys with antibacterial activity against Streptococcus mutans due to the surface structures and inherent properties of PDA-GO. In vitro cytotoxicity tests further verified their good biocompatibility. This bio-inspired nanocomposite coating provides a practical reference for modification of dental metal surfaces to better behave in the intraoral environment.

Knees with anteromedial osteoarthritis show a substantial phenotypic variation prior and following medial unicompartmental knee arthroplasty.

The primary aim of this study was to evaluate the phenotypic variation using the Coronal Plane Alignment of the Knee (CPAK) classification among 1000 knees with anteromedial osteoarthritis (OA) both prior to and following medial unicompartmental knee arthroplasty (UKA). The secondary aim of this study was to investigate whether knees maintained their preoperative CPAK phenotype and to evaluate the phenotypic alterations following medial UKA. The CPAK classification was used to analyze 1000 knees that underwent medial UKA as treatment for anteromedial OA. Knees were categorized into nine distinct CPAK phenotypes based on their arithmetic hip-knee-ankle angle (aHKA), which estimates the pre-arthritic alignment, and joint line obliquity (JLO), both pre- and postoperatively. Phenotypic variation was analyzed by sex and age, and the phenotypic alterations following medial UKA were evaluated by phenotype. Preoperatively, CPAK phenotype I had the highest prevalence (45.0%). Among males, the preoperative prevalence of CPAK phenotype I was significantly higher compared to females (53.2% vs. 35.0%, respectively; p ≤ .001), whereas females exhibited a significantly higher occurrence of CPAK phenotype V compared to males (9.8% vs. 4.4%, respectively; p ≤ .015). Following medial UKA, CPAK phenotype II had the highest prevalence (53.3%). Overall, 45.1% of knees maintained their preoperative CPAK phenotype following medial UKA, which was most frequently observed among CPAK phenotype II (67.7%) and III (65.8%). There is a substantial variation in CPAK phenotypes among knees with anteromedial OA, as well as following treatment with medial UKA. This variability challenges the assumption of uniform characteristics among knees with an identical wear pattern associated with anteromedial OA and emphasizes the complexity and variability of this specific form of OA. III, Retrospective cohort study.

Improved field uniformity in EMC chamber for 6G communication

<span>This paper shows electromagnetic field uniformity in an electromagnetic compatibility (EMC) chamber that is used as a test facility for measuring electromagnetic interference and radiated immunity of 6G communication systems. While not defined yet, 6G radio frequency will work in the wavelength ranges above 95 GHz. With this reason, this paper designed a schroeder-type quadratic residue diffuser for 95 GHz to generate a uniform electromagnetic field in the EMC chamber and studied the field uniformity characteristics in it. To analyze the distribution of electromagnetic fields inside the EMC chamber, finite-difference time-domain (FDTD) numerical analysis method is used. The simulation results show that the EMC chamber with this diffuser satisfies the requirements of international standards and has improved the field uniformity in the chamber.</span>

Investigation of structural, topological, and electrical properties of scheelite strontium molybdate for electronic devices

This article describes the synthesis (solid-state reaction) and characterizations of a scheelite strontium molybdate. The consistency of lattice parameters by N-TREOR09 and the Le-Bail Rietveld refinement method supports the tetragonal crystal system. The spectrum of the pair distribution function (PDF) depicts the orientations of atoms within a tetragonal symmetry. The Williamson-Hall plot examines the average crystallite size (86 nm) and micro-lattice strain (0.00091). The scanning electron microscopic image, energy dispersive X-ray (EDX) spectra, and elemental mapping confirm the uniform and isotropic characteristics of the synthesized material, purity and compactness, and topographic roughness according to ISO25178 standards. The investigation of dielectric, impedance, and conductivity spectra confirms the presence of Maxwell-Wagner dielectric dispersion, relaxation, and influential transport phenomena across a broad spectrum of experimental frequencies (ranging from 1 kHz to 1 MHz) and temperatures (from 25 °C to 500 °C). The observed temperature-dependent resistance characteristics validate that the prepared material is well-suited for applications involving PTC thermistors, sensors, and other related devices. The scaling properties of the modulus data provide evidence for a non-Debye relaxation mechanism. The values of the varistor constant, β1, β2, and β3, which are 1.414, 2.362, and 9.654, respectively, indicate the existence of Ohmic conduction, trap-limited space charge limited conduction (SCLC), and trap-filled SCLC mechanisms suitable for electronic devices.

Heat behavior and axial temperature distribution of a Ti-6Al-4V alloy in a superconducting induction heater with a controllable magnet structure

Ti-6Al-4V (TC4) metal billets can usually be preheated by gases, resistance furnaces, and conventional induction heater powered by alternating current. However, the disadvantages of these heating methods are long heating time and small skin depths. The novel superconducting induction heater has several advantages in terms of heating quality, heating efficiency, heating time and axial temperature control. It has gained successful commercial application in the large aluminum extrusion industry in 2021. However, no studies on TC4 heating behavior using a superconducting induction heater have been reported, and no studies on uniform and gradient temperature characteristics of TC4 in superconducting induction heater. The uniform temperature distribution of TC4 is helpful to reduce the heating residual stress of forgings. The gradient temperature distribution of TC4 billet can obtain different properties in different parts of the same TC4 billet, which is suitable for manufacturing functionally graded materials. In this study, a high-temperature superconducting (HTS) direct-current (DC) induction furnace was firstly used to perform heating experiments for TC4 metal billets of 1250 mm length and 220 mm diameter. The application of the superconducting magnet for induction heating allows for high-power and fast heating of the TC4 billet at an extremely low frequency (4 Hz). The HTS induction heater technology has the advantages of high penetration depth, high energy efficiency (>82%), high heating uniformity, and controllable temperature distribution. Additionally, it improves the metal heating quality and reduces the heating cost. The 10 identical iron pieces of superconducting magnet on both sides of the iron core can be adjusted independently. The gradient and uniform temperature distributions of the thermally optimized TC4 billets were experimentally determined using adjustable electromagnetic heating power. Subsequently, the heating behavior of TC4 billets was modeled and compared using the numerical multiphysical finite element method; the results obtained using this method are in agreement with the experimental results. An expert database has been established for the heating strategy of TC4 billets. The optimized axial temperature distribution was analyzed for three different TC4 billet diameters (Φ220, Φ300, and Φ446 mm). The obtained gradient and uniform axial temperature distributions had an error of less than ±3 °C, and the adjustable difference at two-ends temperature of TC4 billets was in the range 10–100 °C/m. Finally, the maximum thermal stress on the TC4 billet during heating also was analyzed. The results of this study will be useful of the novel HTS induction heater application for TC4 billet heating, and axial temperature control. The uniform temperature distribution control will reduce the heating residual stress of forgings. The gradient temperature distribution of TC4 billet is suitable for manufacturing functionally graded materials.

Highly uniform resistive switching characteristics of KGM resistive memory through air plasma technology

In this study, a highly stable resistive switching behavior was obtained by utilizing konjac glucomannan, a biomaterial, as a dielectric layer through a solution-based process, and the ITO bottom electrode was modified by using an air plasma technique. Electrical results showed that the pretreatment device did not observe significant switching characteristics (∼101). The device, which underwent additional plasma treatment, was recognized for its significant improvements in this area, demonstrating a reduced set voltage (Vset = 0.37 V) with a 6% coefficient of variation, more than 200 consecutive cycles, and up to 90% electrical yield. Moreover, the treated device exhibited a dramatically higher memory window (>104) due to the relatively low off-state current. According to the XPS and UPS analysis, the work function increased from an untreated 4.3 to 5.79 eV as the treatment time increased to 180 s. The conductive filaments, which stemmed from oxygen vacancies, were introduced through plasma treatment to enhance the proportion of oxygen vacancies in the ITO films, thereby creating a stable and consistent filament path. Consequently, the systematic and reproducible resistive switching phenomenon was intensified. The reported results confirmed that the reliability and uniformity in bioelectronic devices can be accomplished through a simple and effective plasma technique. This approach paved the way for alternative applications of these devices.

A novel gas supply configuration for hydrogen utilization improvement in a multi-stack air-cooling PEMFC system with dead-ended anode

The gas supply configuration would influence the reactant distribution, output performance, and durability of multi-stack proton exchange membrane fuel cells (PEMFCs). However, few researches have been conducted on optimizing the gas supply configuration. In this work, the hydrogen supply systems of two air-cooling PEMFC stacks under dead-ended anode (DEA) mode are connected in parallel and series configuration, and effects of configuration method on the performance, uniformity, and purging characteristics of these PEMFC stacks are studied. The experimental results show that series configuration provides higher power output at the expense of lower fuel utilization in comparison with parallel configuration. The main cause for the voltage degradation of PEMFCs systems under DEA mode is the accumulation of impurity gas in the outlet of PEMFC stack. Therefore, an optimized series gas configuration is proposed by adding a buffer tank and solenoid valves at the outlet of PEMFC system to purge and store the impurity gas. The optimized series configuration extends purging interval from 125 s to 800 s at the current density of 200 mA cm−2 without parasitic power. The fuel utilization has been improved from 97.51% (in series), 98.87% (in parallel) to 99.21% (in optimized series).