Dependence Of Resistance Research Articles

Structural, electronic and superconducting properties of room temperature deposited VN[formula omitted] thin films

In recent years, vanadium mononitride (VN) thin films have emerged for their multifaceted functionalities e.g. as electrodes in battery and supercapacitors, as catalysts for hydrogen and oxygen evolution reactions, as superconductors for hot-electron bolometer detectors. In this study, we investigate the structural, electronic and superconducting properties of polycrystalline VNx thin films synthesized at room temperature using a reactive dc magnetron sputtering. The structural evolution of VNx samples with increase in partial N2 gas flow (RN2) during the reactive sputtering and corresponding change in the oxidation states were systematically studied. At a first glance, no visible changes appear in the lattice parameters within RN2= 5–50% samples. Despite this, only RN2 = 5 and 10% samples exhibit superconductivity. Probing the electronic structure around the V L-edges and O, N K-edge again did not reflect any minimal changes in RN2 = 5–100% samples. Across the V K-edge, the oxidation state was also found to be similar. However, the ambiguity was resolved from the Fourier transformed EXAFS spectra immediately revealing presence of a higher number of cationic vacancies. These vacancies drive the VNx system towards poor metals exhibiting dρ/dT = negative in the temperature dependent resistivity. This is in sharp contrast to the previous reports so far exhibiting positive slopes evident for metals. The present work insights on several ambiguities observed for the first time in the V-N system. The work further emphasizes the need to perform a similar study on epitaxially grown VNx thin film samples with reduced defects.

The effect of medium doses electron irradiation on the scattering of charge carriers in YBa2Cu3O7-δ single crystal

The influence of electron irradiation with energies of 0.5–2.5 MeV with fluences up to 70 × 1018 cm–2 on the electrical resistivity in the basal plane of YBa2Cu3O7–δ single crystals in the temperature range from the superconducting transition, Tc, to 300 K has been studied. Such irradiation leads to the appearance of a significant number of defects that cause a decrease in anisotropy, an appreciable increase in phonon scattering, reduction of Tc, and broadening of the superconducting transition. Under the conditions specified, the temperature dependence of electrical resistivity is approximated with high accuracy by the charge carriers’ scattering on defects and phonons, and fluctuating conductivity in the Lawrence-Doniach (LD) model. The dependences of approximation parameters on fluence are discussed.

Thermally conductive polymer materials with high dielectric characteristics based on oligodimethylsiloxane with terminal hydroxyl groups

The results of studying a polyfunctional heat-resistant composition based on oligodimethylsiloxane with terminal hydroxyl groups filled with boron nitride are presented. The influence of boron nitride on the physical-mechanical, thermophysical and electrical properties of the sealing composition is shown. The dependence of thermal conductivity coefficient, electrical resistivity and other characteristics on the content of the modifier has been established.

Assessment of superconducting and structural stability of advanced Y-123 and Y-358 ceramics with Tb/Y substitution in main matrices

In this study, the performances of Y1-x(Tb)xBa2Cu3O7-δ (Y-123) and Y3-x(Tb)xBa5Cu8O18-δ (Y-358) advanced ceramics prepared by sol-gel preparation route are investigated by the advanced characterization methods including X-ray diffraction (XRD), temperature dependent resistivity (ρ-T), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM) and energy distribution spectroscopy (EDS) measurements and theoretical approaches. The EDS results illustrated that the Tb impurities were replaced successfully by the yttrium sites in the YBa2Cu3O7-y main matrix. Similarly, it was noted that the presence of excess impurities in the crystal structure led to the oxygenation problems. Electrical properties were determined by temperature dependent resistivity (ρ-T) measurements. ρ-T results indicated that Tb doping reduced the critical transition temperature (Tc) values for the transition to superconductivity for all samples in two YBCO phases. Although it appears to have negative effects of Tb ions on the number of mobile charge carrier concentrations in the σ antibonding in-plane Cu-O bonds, bipolaron formations in the polarizable lattices, oxidation states, and amplitude of the pair wave function of both phases, the other valuable properties (morphology, crystallinity quality, interaction between adjacent layers, critical current density, and flux pinning ability) were noted to improve remarkably in the case of the optimum amount in the Y-123 superconducting phase. In this context, the Y-358 superconducting phase was harshly affected by the substitution due to the change of the ortorombicity, localization problem, impurity phases, structure stabilization, crystal structure quality, crystallization system, homogeneities of oxidation states, oxygen ordering degree, and impurity scatterings. Besides, the analysis of the fluctuation induced conductivity indicated that the Y-123 ceramics with longer c-axis coherence length and less anisotropic nature exhibited well superconducting properties. Additionally, the doping ratio of x=0.01 led to the formation and distribution of more nucleation centers for the thermal fluxon motions of 2D pancake vortices. Similarly, the optimum Tb doped Y-123 system exhibited much durable to applied field strengths due to the best interaction quality between grains. Accordingly, this study recommended that the Y1-x(Tb)xBa2Cu3O7-δ advanced ceramic structure with new functionalities can find much more application areas in innovative, heavy-industrial technologies, and advanced engineering-related sectors.

Bending, electroadhesion and sensing performances of single compliant electrode dielectric elastomer actuator based on SEBS gel

Dielectric elastomer actuators (DEAs) have great potential for application in soft robotics due to their ability to undergo substantial deformations, rapid response times, and high energy density when subjected to external electrical stimuli. However, the application of DEAs in the field of soft grippers is limited by their restricted direct electro-bending capability, output force, self-sensing capacity, and pre-stretching requirement. In this study, we fabricated a single compliant electrode DEA (SCE-DEA) which was made by sandwiching a compliant electrode between two layers of poly(styrene-b-ethylene-co-butylene-b-styrene) (SEBS)/white mineral oil (WO) dielectric elastomer films. The SCE-SEBS/WO was demonstrated to have the capacities of bending, sensing, and electroadhesion (EA). The SCE-SEBS/WO can be used in various soft actuator modes, such as the unipolar EA actuator, soft gripper, and soft vibrator. The grabbing mechanism of SCE-SEBS/WO-based soft grippers with opposite bipolar configuration is caused by electric field induced bending of SEC-SEBS/WO and subsequent electrostatic attraction between both SEC-SEBS/WO. The SEC-SEBS/WO based soft grippers have rapid response detachment, and ability to grasp various types of objects. Three-layer stacked SCE-SEBS/WO-60 (with 60 wt% of WO) exhibited 531 mN cm−2 of EA stress on the paper at 3.0 kV applied voltage, and the soft gripper made by four SCE-SEBS/WO-60 can successfully grab wood blocks weighing 162.4 g at 5 kV applied voltage. The sensing capacity of SCE-SEBS/WO based soft gripper was based on the bending strain dependent resistance changes of the compliant electrode. Our results provide new insights into the fabrication of DEA based soft grippers.

Structural and electronic transport properties of Zn- and Ga-doped Bi2− x Sb x Te3− y Se y topological insulator single crystals

A comprehensive study of structural and magnetotransport properties of pristine Bi2−x Sb x Te3−y Se y (BSTS) single crystals and doped with Zn (BSTS:Zn) and Ga (BSTS:Ga) are presented here. Magnetic field dependent Hall resistivities of the single crystals indicate that the holes are the majority carriers. The field dependent resistivity curves at different temperatures of the crystals display cusp-like characteristics at low magnetic fields, attributed to two-dimensional (2D) weak antilocalization (WAL) effect. We fit the observed low-field WAL effects at low temperatures using 2D and three-dimensional (3D) Hikami-Larkin-Nagaoka (HLN) equations. The 2D HLN equation fits the data more closely than the 3D HLN equation, indicating a 2D nature. The 2D HLN equation fit to the low field WAL effects at various temperatures reveal a phase coherence length (l φ) that decreases as temperature increases. The variation of l φ with temperature follows T −0.41 power law for BSTS:Zn, suggesting that the dominant dephasing mechanism is a 2D electron–electron (e−e) interactions. For pristine BSTS and BSTS:Ga, l φ(T) is described by considering a coexistence of 2D e−e and electron–phonon (e−p) interactions in the single crystals. The temperature variation of the longitudinal resistance in BSTS:Ga is described by 3D Mott variable range hoping model. In contrast, the transport mechanisms of both pristine BSTS and BSTS:Zn are described by a combination of 2D WAL/EEI models and 3D WAL.

Temperature Evolution of Composition, Thermal, Electrical and Magnetic Properties of Ti3C2Tx-MXene.

MXenes are a family of two-dimensional nanomaterials. Titanium carbide MXene (Ti3C2Tx-MXene), reported in 2011, is the first inorganic compound reported among the MXene family. In the present work, we report on the study of the composition and various physical properties of Ti3C2Tx-MXene nanomaterial, as well as their temperature evolution, to consider MXenes for space applications. X-ray diffraction, thermal analysis and mass spectroscopy measurements confirmed the structure and terminating groups of the MXene surface, revealing a predominant single OH layer character. The temperature dependence of the specific heat shows a Debye-like character in the measured range of 2 K-300 K with a linear part below 10 K, characteristic of conduction electrons of metallic materials. The electron density of states (DOS) calculations for Ti3C2OH-MXene reveal a significant DOS value at the Fermi level, with a large slope, confirming its metallic character, which is consistent with the experimental findings. The temperature dependence of electrical resistivity of the MXene samples was tested for a wide temperature range (3 K-350 K) and shows a decrease on lowering temperature with an upturn at low temperatures, where negative magnetoresistance is observed. The magnetoresistance versus field is approximately linear and increases its magnitude with decreasing temperature. The magnetization curves are straight lines with temperature-independent positive slopes, indicating Pauli paramagnetism due to conduction electrons.

Electrical resistivity and magnetoresistance of Sr3Fe2+xMo1–xO9–3x/2 (x = 0.45, 0.60, and 1.00) prepared by the solid-state reaction

In this paper, we focus on understanding the behavior of the temperature dependence of electrical resistivity (ρ) and magnetoresistance (MR) in Sr3Fe2+xMo1–xO9–3x/2 perovskites with x = 0.45, 0.60, and 1.00. Three polycrystalline materials were synthesized using conventional solid-state reaction techniques. Rietveld analysis of room-temperature X-ray diffraction data reveals that all three compositions crystallize in tetragonal symmetry; where x = 0.45 and 0.60 undergo an I4/mcm space group, while x = 1.00 adopts a P4/mmm space group. Electrical resistivity measurements carried out at magnetic fields (0 and 1 T) reveal the presence of a transition from the ferromagnetic phase to the paramagnetic phase in the vicinity of the TMI. The metal-insulator transition temperature (TMI) decreases with increasing Fe content and rises slightly with changing magnetic field from 0 to 1 T. The magnetoresistance (MR) of the SrFeO3–δ sample (x = 1.00) has a large value of about 63.6 %, indicating that it can be exploited for certain devices. A variety of theoretical models are used to study the behavior of electrical resistivity in various temperature ranges, showing excellent agreement with experimental results.

THE PREVALENCE AND RISK FACTORS FOR ARTERIAL HYPERTENSION IN CHILDREN WITH IDIOPATHIC NEPHROTIC SYNDROME

Objective: Arterial hypertension (AH) is claimed to be an uncommon finding in children with idiopathic nephrotic syndrome (INS). The study aimed to analyze blood pressure, prevalence, and risk factors of AH in children with INS. Design and method: In 153 children with INS (9.32±3.84 years, 100 boys), we evaluated systolic and diastolic blood pressure (mm Hg, Z-scores), age at onset of the disease, anthropometric data, response to steroids, results of kidney biopsy, number of INS relapses, and medications. Results: The mean age at disease onset was 4.39±2.38 years; 67 patients had steroid-sensitive nephrotic syndrome (SSNS), 12 frequently relapsing nephrotic syndrome (FRNS), 58 steroid-dependent nephrotic syndrome (SDNS), and 16 steroid-resistant nephrotic syndrome (SRNS). Kidney biopsy was performed in 26: 5 – minimal change disease, 11 – mesangial proliferation, 10 – focal and segmental glomerulosclerosis. AH at disease onset was found in 10 (6.5%) patients in the following 11 (7.2%) after corticosteroid initiation. The observation period was 4.93±3.80 years, and AH was found in 31 (20.3%) – in 3 (4.5%) patients with SSNS, 2 (16.7%) with FRNS, 20 (34.5%) with SDNS, and 6 (37.5%) with SRNS. Patients with AH had lower height Z-score (-0.46±1.20 vs. 0.18±1.15, p=0.006), higher BMI Z-score (1.15±1.10 vs. 0.41±1.09, p<0.001), number of INS relapses (8.32±6.78 vs. 4.41±3.82, p<0.001), and current prednisone dose (0.49±0.67 vs. 0.18±0.29 [mg/kg/24h], p<0.001). Systolic blood pressure Z-score at the end of observation correlated with age (r=-0.192, p=0.017), BMI Z-score (r=0.368, p<0.001), and present prednisone dose [mg/kg/24h] (r=0.186, p=0.021), diastolic blood pressure Z-score with BMI Z-score (r=0.231, p=0.004), and number of INS relapses (r=0.163, p=0.044). In Cox Proportional Hazard presence of SDNS and SRNS were the only predictors of AH (SDNS: HR=4.80, 95CI(1.30-17.75), SRNS: HR=4.77, 95CI(1.06-21.53)). Conclusions: 1. Approximately one-third of patients with SDNS and SRNS develop arterial hypertension in the course of the disease. 2. Steroid dependence and steroid resistance are the strongest predictors of AH in children with INS. Other determinants of blood pressure elevation in this group of patients are high BMI and a high number of relapses.

COMPREHENSIVE OVERVIEW OF ADAPTOR PROTEIN RUK/CIN85 ROLES IN CANCER

Aim. This study is focused on a comprehensive overview of mechanisms and processes involved in the acquisition of cancer cell plasticity in a manner dependent on the adapter protein Ruk/CIN85 (in rodents, Ruk — regulator of ubiquitous kinase; in human CIN85 — Cbl-interacting protein of 85 kDa, encoded by SH3KBP1 gene).. Methods. Gene expression was evaluated using RT2-PCR and Western blotting, cell proliferation and survival were analyzed using MTT and/or dye exclusion assays, motility was assessed by scratch test and Transwell assay, enzyme activities were measured using spectrophotometric assays. In vivo metastasis were studies using experimental metastasis model. Conclusion. This study discloses various aspects of cancer cells plasticity, such as EMT, stemness, metabolic changes, ECM components, and drug resistance in dependence on adaptor protein Ruk/CIN85 expression level.

Design modification of elliptical vessel solar receiver by response surface methodology

Design modification of elliptical vessel solar receiver system by response surface methodology has been carried out. The materials used in this study were locally sourced from Kenyeta Market Enugu, Onitsha Bridge Head Market, and Idumota Market Lagos. These materials were sourced based on categories of components element: support mechanisms made of mild steel plates, bolts, nuts, clamps, and water as heat transfer fluid. The reflector is made of aluminum foil tape while the vessel has a glass cover fitted with bolts and nuts, the receiver is made of copper pipe, aluminum pipe, galvanized iron pipes, and stainless steel pipes. The pipes were fitted into the vessel with chlorinated polyvinyl chloride 3⁄4 joint pipes, and journal-bearing mechanisms. Other features include the tracking system made of light dependent resistance sensors, a direct current motor, a pulley, a belt, an Arduino controller, and a thermal energy storage tank. The lagging material was an expanded Polyethylene sheet. Experimental data were measured with thermocouples, a digital panel, a Uni-T digital anemometer (UT363), and a digital solar power meter (SM206-SOLAR). Matrix Experimental design was used to develop an experimental model for the system. The developed system was tested to investigate the effect of various heat collectors with and without coating on its performance. It was established from the response optimization that the intercept factor was improved by 32.2%. Similarly, the theoretical efficiency was improved by 8.19% while the experimental thermal efficiency was improved by 6.99%.

Flexible PVA/Mn Ferrite/(MoS2)x Nanocomposites With Electromagnetic Wave Absorption Performance for Light Dependent Resistances

AbstractThe presence of electromagnetic pollution not only poses a threat to human health but also disrupts the proper functioning of large‐scale machinery. In light of this, a novel method involving sol–gel techniques was utilized to synthesize PVA/Mn Ferrite/(MoS2)x nanocomposites, which exhibit remarkable electromagnetic wave absorption properties. By intelligently combining MoS2 with PVA/Mn Ferrite, the composite's electromagnetic parameters were optimized, leading to enhanced impedance matching. As a result, the PVA/Mn Ferrite/(MoS2)x nanocomposites showcased an exceptional minimum reflection loss of −15.971 dB at a thickness of 1 mm. The remarkable capability of absorbing substances can primarily be attributed to the outstanding synergistic interaction between PVA/Mn Ferrite and MoS2. Additionally, MoS2 also plays a significant role in generating dielectric loss and achieving ideal impedance matching. As a result, the potential applications of PVA/Mn Ferrite/(MoS2)x nanocomposites extend to serving as both absorption materials and light dependent resistance (LDR) sensors. These nanocomposites exhibit not only high efficiency but also possess the added advantages of flexibility and lightweight properties, further enhancing their desirability.

On the Voltage Dependent Series Resistance, Interface Traps, and Conduction Mechanisms in the Al/(Ti-doped DLC)/p-Si/Au Schottky Barrier Diodes (SBDs)

In this study, Al-(Ti:DLC)-pSi/Au Schottky barrier diode (SBD) was manufactured instead of conventional metal / semiconductor (MS) with and without an interlayer and then several fundamental electrical-characteristics such as ideality factor (n), barrier height B series and shunt resistances (Rs, Rsh), concentration of acceptor atoms (NA), and width of depletion-layer (Wd) were derived from the forward-reverse bias current/voltage (I-V), capacitance and conductance as a function of voltage (C/G-V) data using various calculation-methods. Semi logarithmic IF-VF plot shows a linear behavior at lower-voltages and then departed from linearity as a result of the influence of series resistance/Rs and organic-interlayer. Three linear regions can be seen on the double-logarithmic IF-VF plot. with different slopes (1.28, 3.14, and 1.79) in regions with low, middle, and high forward bias, which are indicated that Ohmic-mechanism, trap-charge-limited-current (TCLC) mechanism, and space-charge-limited-current (SCLC) mechanism, respectively. Energy dependent surface states (Nss) vs (Ess-Ev) profile was also obtained from the Card-Rhoderick method by considering voltage-dependence of n and B and they were grown from the mid-gap energy up to the semiconductor's valance band (Ev). To see the impact of Rs for 1 MHz, the measured C/G-V graphs were amendment. All results are indicated that almost all electrical parameters and conduction mechanism are quite depending on Rs, Nss, and calculation method due the voltage dependent of them.

Glucose dependent resistance associated with intestinal microbiota facilitate teleost to survive bacterial infection

Host microbiota interaction affects the metabolism and immune regulation in the host. To explore the disease resistance mechanism and the host-microbiota interaction details, the intestinal transcriptome and microbiome of moribund and surviving fish infected with Aerompnas hydrophila as well as healthy controls were cross-analyzed. Survivors presented an intestinal microbiome with slight change and more intensive interspecies cooperation, while a distinct gene expression profile related to glycometabolism and immunomodulation was observed, resulting in lower-level inflammation in intestinal tissue. Genes related to FoxO, Insulin, and Glucagon signaling pathways, such as g6pc, socs2, and foxg1, correlated positively with intestinal Eubacterium_coprostanoligenes_Group, Mannheimia, Leptotrichia, and Shewanella, corresponding to a higher serum glucose level and IgM titer in surviving fish. Besides, Pseudomonas and Shewanella, with higher abundance in surviving fish, showed antagonism towards the pathogen in vitro, and a positive correlation with serum glucose level and IgM titer, respectively. Co-cultures promoted these antagonism effects and these effects connected with glucose concentration. Glucose supplementation to fish raised the survival rate significantly. In general, glycometabolism homeostasis is critical for fish to survive A. hydrophila infection. Metabolism modulation would be a potential approach to facilitate bacterial infection resistance.

Abstract 6500: Dependence of EGFR-mutant NSCLC on MET as demonstrated by vebreltinib, a novel and selective brain-penetrating MET kinase inhibitor

Abstract Background: Although EGFR inhibitors (EGFRi), preferably osimertinib, have offered substantial benefit for the classical plus T790M EGFR-mutant NSCLC patients, drug resistance develops and poses a critical challenge for long-term survival. The resistance is rooted to either on-target secondary EGFR mutations or compensatory oncogenic pathways bypassing EGFRi intervention, one of which appears to be treatment-acquired MET amplification (METamp). In this study we set out to understand the conditions when the tumor cells become dependent on MET. Methods: NSCLC patient-derived tumor models (PDX) carrying classical and T790M EGFR driver mutations were selected based on EGFRi history and concurrent MET gene copy numbers or RNA expression levels: Type 1) resistant to osimertinib with METamp; Type 2) partially resistant to osimertinib with METamp; and Type 3) sensitive to osimertinib with low MET expression, no METamp. These PDX xenograft mice were treated with vebreltinib (APL-101) at clinically relevant doses as single agent or in combination with osimertinib. The pharmacodynamic effects on EGFR and MET phosphor (P)- and total proteins were analyzed from tumor samples harvested during and at the end of treatments. Results: Vebreltinib single agent inhibited tumor growth of the type-1 PDX. One such PDX was resistant to chemotherapies, BRAF inhibitor and EGFRi including osimertinib, was inhibited by vebreltinib with ED50 of 3 mg/kg (p.o/q.d.). Another such PDX tumor appeared to be eradicated by vebreltinib treatment at 10 mg/kg (p.o/q.d.) and the mice became tumor-free on Day 18 and remained so after dosing stop on day 21 with last observation at study end (Day 70). In comparison, reference METi savolitinib showed only partial tumor size reduction against the same PDX tumor, not as durable as vebreltinib, and did not eradicate tumor growth at the same dose as vebreltinib or in combo with Osimertinib. Re-grown tumor after savolitinib osimertinib combo dosing stop was inhibited completely by vebreltinib follow-on treatment. In the type-2 PDX, tumor growth was partially inhibited by vebreltinib but was completely inhibited by combo of vebreltinib and osimertinib. The anti-tumor activity of vebreltinib in type-1 and type-2 PDX was associated with pharmacodynamic inhibition of P-MET and P-EGFR and MET protein degradation. In the type-3 PDX, tumor growth appeared to be eradicated by osimertinib and not inhibited by vebreltinib. However, addition of vebreltinib suppressed tumor re-growth after osimertinib dosing stop. Conclusion: EGFR-mutant NSCLC resistance to EGFRi may be dependent on MET pathway regardless of acquired METamp, whereas METamp may dictate the degree of MET dependence. Our data supports the hypothesis that adding vebreltinib to EGFRi overcome MET dependent resistance with durable effect or preventing MET dependent resistance to maximize therapeutic benefits. Citation Format: Xiaoling Zhang, Elaine Liu, Yan Song, Peony Yu, Sanjeev Redkar, Guo-Liang Yu. Dependence of EGFR-mutant NSCLC on MET as demonstrated by vebreltinib, a novel and selective brain-penetrating MET kinase inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6500.

Enhanced structural, optical and electrical properties of polycrystalline WO3 thin films achieved by aluminum nanosheets coating

Herein the effects of aluminum nanosheets on the structural, morphological, optical and electrical properties of tungsten oxide thin films are reported. Polycrystalline phase of the thermally evaporated WO3 was achieved by the pulsed laser welding technique. The polycrystalline films are then coated with Al nanosheets of thicknesses of 100 nm and 150 nm by the ion coating technique. It is observed that Al induces the domination of the hexagonal structure of WO3 over the tetragonal. Associated with the enhanced crystallinity the light absorption in the films increased by more than 60% and the energy band gap narrowed significantly. Namely the energy band gap of the as grown WO3 decreased from 3.15 eV to 2.85 eV and 2.59 eV as the Al layer thickness increased from 100 to 150 nm, respectively. It is also observed that crystalline films of WO3 exhibited lower electrical resistivity compared to films fabricated by other techniques. The temperature dependent electrical resistivity measurement was carried out in the temperature range of 310–420 K. It showed room temperature values of 2.5 ( Ω cm), 2.2 ( Ω cm) and 1.9 ( Ω cm) and impurity levels centered at 0.25 eV, 0.34 eV and 0.16 eV for uncoated and films coated with Al nanosheets of thicknesses of 100 nm and 150 nm, respectively. The enhanced crystallinity that is accompanied with narrower energy band gap and lower electrical resistivity values make crystalline WO3 films promising for optoelectronic applications.

Evaluating SWCNT assembly properties from the temperature dependence of electrical resistivity

We developed a theoretical model to describe the electrical resistivity in films and fibers made of single-walled carbon nanotubes (SWCNTs). The proposed model considers the formation of randomly oriented bundles of metallic and semiconducting nanotubes and takes into account the influence of temperature, while separating contributions of SWCNTs and their junctions to the total resistivity. To verify the model, we applied a powerful experimental tool – measurements of the temperature dependence of electrical resistivity of the investigated macroscopic SWCNT assemblies (pristine and doped SWCNT fibers). This allowed us to estimate various parameters of the material, such as the average length of SWCNT bundles, the acoustic phonon scattering length, and the bundle contact resistance, which are difficult to evaluate experimentally for entangled SWCNTs. The study highlights the importance of understanding the relationship between structural characteristics and electrical properties in SWCNT assemblies. The findings provide insights into optimizing the conductivity of these materials and offer a quick estimation method of the SWCNT network properties based on varying temperature measurements for future fiber and film-based applications.

High performance low power multilevel oxide based RRAM devices based on TiOxNy/Ga2O3 hybrid structure

In this study, the resistive memory devices with Ag/TiOxNy/Pt structure and Ag/TiOxNy/Ga2O3/Pt structure are fabricated. The results showed that they exhibit typical resistive behaviors as well as excellent cycling and retention characteristics (>104 s). Especially, the double-layer device with Ga2O3 layer exhibits superior resistive behavior, which has a larger storage window (ON/OFF ratio >105), a smaller set voltage (0.17 V) and a reset voltage (−0.057 V), and lower power consumption (21.7, 0.17 μW) compared with the single-layer device. Furthermore, the Ag/TiOxNy/Ga2O3/Pt device demonstrates ultraviolet light (UV-365 nm)-dependent resistance state (RS), which is advantageous for multilevel memory cells. As the intensity of UV light increases, eight high resistance state (HRS) levels are produced. Finally, the conductive mechanism for both device structures is discussed, and it is found that the conductive filaments mechanism dominates in the low resistance state. However, for the HRS, the single-layer TiOxNy device is dominated by the space charge-limited conduction mechanism, and the double-layer TiOxNy/Ga2O3 device is dominated by the Schottky emission mechanism.

Carbon addition and temperature dependent tensile deformation resistance and capacity of a low-cost 3rd-generation Ni-based single crystal superalloy

A balance between the mechanical performance and castability of Ni-based single crystal superalloys is expected to be achieved by doping with appropriate carbon content. In this study, the influences of carbon content on the tensile properties of a novel low-cost 3rd-generation Ni-based single crystal superalloy at 760 °C and 1120 °C were investigated. Results showed that minor carbon addition could slightly increase the strength and plasticity of the experimental alloy at 760 °C, whereas it led to the decrease of strength and plasticity at an elevated temperature of 1120 °C. This variability was discussed in terms of the microscopic resistance for dislocation movement and the macroscopic deformation capacity associated with damage accumulation. It was found that the solid solution strength and interface strength were enhanced with increasing carbon content, however, the strength at high temperature was compromised by the enormous consumption of refractory elements, even though the precipitation of blocky M6C carbides provided additional hindrance. As for the macroscopic deformation capacity, interdendritic carbides could hinder the extension and/or trigger the activation of slip bands at 760 °C. Nonetheless, the initiation tendency and propagation behavior of microcracks at 1120 °C were facilitated due to the strong stress concentration and severe deformation incompatibility of interdendritic carbides. Overall, future compositional optimization should focus on reducing the formation of Ta-enriched MC carbides to minimize the loss of refractory element reinforcement and the reduction of deformability at high temperatures.

Efficacy of colchicine in addition to anakinra in patients with recurrent pericarditis

AimAnakinra, an anti IL-1 agent targeting IL-1 alfa and beta, is available for the treatment of recurrent pericarditis in cases with corticosteroid dependence and colchicine resistance after failure of conventional...