- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Structural and Superconducting Properties of Thermal Treatment-Synthesised Bulk YBa2Cu3O7?δ Superconductor: Effect of Addition of SnO2 Nanoparticles
摘要： YBa2Cu3O7?δ (Y-123) bulk superconductors with the addition of (0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 wt.%) SnO2 nanoparticles were synthesised via a thermal treatment method. The in?uence of SnO2 addition on the superconducting properties by means of critical temperature, Tc, AC susceptibility, phase formation and microstructures, including its elemental composition analysis, were studied. Sharp superconducting transition, ?Tc, and diamagnetic transition were obtained for all SnO2-added samples. It was observed that sample x = 0.4 with a Y-123 phase percentage of 95.8% gives the highest Tc, smallest ?Tc, and the sharpest diamagnetic transition in the normalised susceptibility curves. The microstructure also showed an excess of Sn precipitates on the sample’s surface at x = 0.8 and above. As such, the best superconducting properties were observed at x = 0.4 SnO2 addition inside the Y-123 host sample.
关键词： YBa2Cu3O7?δ,bulk superconductor,additions,SnO2,thermal treatment method
更新于2025-09-23 15:23:52
-
[IEEE 2018 International Flexible Electronics Technology Conference (IFETC) - Ottawa, ON, Canada (2018.8.7-2018.8.9)] 2018 International Flexible Electronics Technology Conference (IFETC) - Optimizing the Electrical Conductivity of Screen Printed Silver Conductive Tracks by Post Treatment
摘要： Screen printed silver conductive tracks have been used or are being explored for applications in membrane switches, solar cells, radio frequency identification (RFID) antennas, diabetic testing strips, sensors etc. For many of these applications, optimizing the electric conductivity of the printed tracks is crucial. It has been noticed that the electric conductivity of the printed conductive tracks are highly dependent on the post-processing conditions. However, the understanding of the effect is limited. In this paper, preliminary study results show that ambient temperature drying followed by heat treatment offers the lowest resistance (highest conductance) for printed conductive tracks.
关键词： Electrical Conductivity,Printed Conductive Tracks,Post Thermal Treatment,Curing
更新于2025-09-23 15:22:29
-
Kinetics of graphitization of thin diamond-like carbon (DLC) films catalyzed by transition metal
摘要： In this paper, we have studied the kinetics of graphitization at 773K of thin diamond-like carbon (DLC) films coated with minute amount of Ni metallic particles. DLC films are deposited at room temperature by pulsed laser deposition (PLD) on a transparent quartz substrate, and Ni is deposited on the surface of DLC using molecular beam epitaxy technique at room temperature. The ultra-high vacuum thermal (range 573-873K with 60 min annealing treatments) and kinetic (range 30-3760 min at 773K) behaviors of the deposited films are investigated. Surface and interface characterizations indicate that the growth of graphitic sp2 clusters starts at temperatures lower than 573K. The kinetics of graphitization is recorded at 773K. Thus, the continuous growth of graphitic clusters leads to a long-range kinetics. These clusters are responsible for the increase in the electrical conductivity and carrier mobility, reaching values of 6.103 Siemens/cm and 20 V/cm2?s, respectively. This continuous change is not only explained by the nucleation and growth of graphitic clusters, but also by some reorientation of them alongside both the surface and the quartz substrate. The obtained results demonstrate that thermally post-treated catalytic metal/DLC films are promising materials for conductive electrodes and sensing applications.
关键词： Raman spectroscopy,thermal treatment,electric transport measurements,optical transmission and absorption,diamond-like carbon,thin graphite films,pulsed laser deposition,metal catalyst
更新于2025-09-23 15:21:01
-
Post-annealed graphite carbon nitride nanoplates obtained by sugar-assisted exfoliation with improved visible-light photocatalytic performance
摘要： Two-dimensional (2D) graphitic carbon nitride (g-C3N4) nanoplates (CNNP) have become a hot research topic in photocatalysis due to their small thickness and large specific surface area that favors charge transport and catalytic surface reactions. However, the wide application of 2D g-C3N4 nanoplates prepared by ordinary methods suffers from increased band gaps with a poor solar harvesting capability caused by the strong quantum confinement effect and reduced conjugation distance. In this paper, a facile approach of exfoliation and the following fast thermal treatment of the bulk g-C3N4 is proposed to obtain a porous few-layered g-C3N4 with nitrogen defects. Due to the preferable crystal, textural, optical and electronic structures, the as-obtained porous CNNP demonstrated a significantly improved photocatalytic activity towards water splitting than the bulk g-C3N4 and even the 3 nm-thick CNNP obtained by sugar-assisted exfoliation of the bulk g-C3N4. The difference in the enhancement factors between the H2O splitting and organic decomposition has revealed the effect of N defects. This study offers insightful outlooks on the scalable fabrication of a porous few-layered structure with a promoted photocatalytic performance.
关键词： Photocatalytic activity,g-C3N4 nanoplates,Co-grinding,Thermal treatment,Sugar
更新于2025-09-23 15:19:57
-
Differences in the local structure and composition of anodic TiO2 nanotubes annealed in vacuum and air
摘要： This work is dedicated to the influence of thermal treatment procedures in vacuum and air atmosphere on the structural features of multiwalled TiO2 anodic nanotubes (NTs) formed in fluorine-containing ethylene glycol (EG) based electrolyte investigated by high-resolution transmission electron microscopy (HRTEM) in conjunction with EDX and electronic nanodiffraction (STEM nanodiffraction), IR and Raman spectroscopy, XPS and ToF SIMS. Using electron nanodiffraction technique, there were estimated TiO2 nanocrystallite sizes for the inner layer of the NTs after annealing in air and vacuum for the first time. The differences in carbon distribution profiles in TiO2 nanotube crosscut after thermal treatments in air and vacuum were discussed. It was found that thermal treatment in vacuum leads to different phase composition of TiO2 NTs IL comparing to annealing in air. A sequential thermal treatment (firstly in vacuum and then in air) enables to remove carbon from TiO2 NTs surface and partly from TiO2 NTs IL and prevent detachment of IL from OL at the same time. The obtained data will be useful for understanding the mechanisms of structural modifications during thermal treatments as well as for functional properties optimization of such nanostructures.
关键词： Anodizing,TiO2 nanotubes,Thermal treatment,Electron nanodiffraction,HAADF-STEM
更新于2025-09-23 15:19:57
-
Tuning the Emission Colors of Self-Assembled Quantum Dot Monolayers via One-Step Heat Treatment for Display Applications
摘要： Homogeneously self-assembled colloidal semiconductor quantum dot monolayers (QD-SAMs) over large areas are promising materials for thin film optoelectronic device applications, especially for display. Although tuning of emission colors from QDs is generally achieved during wet chemical synthesis and before monolayer formation, we propose in this study a simple and effective method to adjust emission colors after the formation of QD-SAMs by a simple one-step heat treatment. CdSe-based core/shell or core/double shell structured QDs (CdSe/ZnS, CdSe/CdZnS, and CdSe/CdS/ZnS) covered with an optimal set of hydrophobic ligands can form homogeneous and stable QD-SAMs at the air-water interface. The QD-SAMs are subsequently transferred onto hydrophobized glass substrates by the Langmuir-Schaefer (LS) method and thermally treated in air. We found a blueshift of more than 35 nm for the emission wavelength (red to green) by a thermal treatment at 280 °C for 150 min with CdSe/ZnS QD-SAMs. The color can be adjusted by changing the heating temperature and the treatment time. The wavelength shift is in the order of CdSe/ZnS(4L) > CdSe/ZnS(6L) = (CdSe/CdZnS) > (CdSe/CdS/ZnS). The energy dispersive X-ray (EDX) microanalysis of a single QD reveals that the blueshift is mainly caused by atomic diffusion-induced alloying of core/shell type QDs. The main problem of this method is the decreasing emission intensity caused by oxidation during the heat treatment; however, this problem can be solved by use of a SiO2 protective coating on the QD-SAMs. We believe that this simple technique is useful for manufacturing RGB-colored ultrathin QD-SAM films for QDs displays such as QD film display, QD color-filter display, and QD light emitting diode.
关键词： QD Display,Quantum dots,Color tuning,Self-assembled monolayer,atomic diffusion-induced alloying,Thermal treatment
更新于2025-09-23 15:19:57
-
Explaining the enhanced photoelectrochemical behavior of highly-ordered TiO2 nanotube arrays: anatase/rutile phase junction
摘要： The effect of calcination temperature on the photoelectrochemical properties of TiO2 nanotube arrays (TNTAs) has been investigated in many studies. Most work focused on improving the photoelectrochemical properties through optimization of the microstructure. In this paper, however, an anatase/rutile phase junction formed in TiO2 nanotubes has been demonstrated to account for the enhancement of the photoelectrochemical performance. Observations by the UV-visible diffuse reflectance spectra, glancing incidence angle X-ray diffraction (GIA-XRD) and electrochemical impedance spectroscopy indicate that the rutile fraction is at the bottom of the nanotubes while the anatase fraction at the body of the nanotubes. The TNTAs with the coexistence of about 60% anatase and 40% rutile exhibit the optimal performance and show the 1.4 times improved photocurrent density compared with the pure anatase TNTAs. Detailed synchrotron radiation photoemission spectroscopy further confirms the existence and effect of the phase junction. The results suggest photogenerated electrons transfer from the rutile phase to anatase phase in the nanotubes due to the band edge alignment, which facilitates the photogenerated carriers separation and transport along the nanotubes and leads to apparent enhancement of the photoelectrochemical behavior.
关键词： photoelectrochemical properties,TiO2 nanotube arrays,phase junction,thermal treatment
更新于2025-09-19 17:15:36
-
Nanostructure and Optical Property Investigations of SrTiO3 Films Deposited by Magnetron Sputtering
摘要： Strontium titanate thin films were deposited on a silicon substrate by radio-frequency magnetron sputtering. The structural and optical properties of these films were characterized by X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and spectroscopic ellipsometry, respectively. After annealing at 600–800 °C, the as-deposited films changed from amorphous to polycrystalline. It was found that an amorphous interfacial layer appeared between the SrTiO3 layer and Si substrate in each as-deposited film, which grew thicker after annealing. The optical parameters of the SrTiO3 film samples were acquired from ellipsometry spectra by fitting with a Lorentz oscillator model. Moreover, we found that the band gap energy of the samples diminished after thermal treatment.
关键词： thermal treatment,strontium titanate film,optical properties,magnetron sputtering
更新于2025-09-19 17:15:36
-
Preheating and thermal behaviour of a rotating cylindrical workpiece in laser-assisted machining
摘要： Laser-assisted machining is a widely used technique for preheating workpiece to reduce cutting forces and promote machinability in metal machining, thereby enhancing manufacturing quality and productivity. In setting laser-assisted machining parameters, the current practice typically relies on trial-and-error approaches. The uncertainties thereof could lead to adverse outcomes in product manufacturing, thus negating the potential benefits of this machining method. A clear understanding of workpiece thermal behaviour under laser spot heating is pivotal to developing a systematic basis for determining required preheating levels and optimised cutting variables for laser-assisted machining. In achieving this, the experimental methods are recognised to be largely impractical, if not tedious, due to instrument limitations and practicality of suitable non-intrusive measuring methods. Conversely, numerical methodologies do provide precise, flexible and cost-effective analytical options, warranting potential for insightful understanding on the transient thermal impact from laser preheating on rotating workpiece. Presenting such an investigation, this article presents a finite volume-based numerical simulation that examines and analyses the thermal response imparted by laser spot preheating on a rotating cylinder surface. On a rotating frame of reference using the ANSYS Fluent solver, the numerical model is formulated, accounting for transient heat conduction into the cylinder body and the combined convection and radiation loses from the cylinder surface. The model is comprehensively validated to ascertaining its high predictive accuracy and the applicability under reported laser-assisted machining operating conditions. The extensive parametric analyses carried out deliver clear insight into the dynamics of thermal penetration occurring within the workpiece due to laser spot pre-heating. This facilitates appropriate consideration of laser preheating intensity in relation to other operating variables to achieve necessary material softening depth at the workpiece surface prior to setting out on the subsequent machining process. Building upon the data generated, a practically simpler and cost-effective preheating parametric predictor is synthesised for laser-assisted machining using neural network principles incorporating the Levenberg–Marquardt algorithm. This predictive tool is trained and verified as a practical preheating guide for laser-assisted machining for a range of operating conditions.
关键词： numerical thermal modelling,Laser-assisted machining,artificial neural network,validation,thermal treatment
更新于2025-09-19 17:13:59
-
Sulfonation of a flexible and unexpected electrically conductive polysulfone and its performance in perovskites solar cells
摘要： The effect of sulfonation on polysulfone regarding its electrical properties is studied and discussed. In addition to the effect of percentage of sulfonation, the thickness of thin films and the ultraviolet (UV) treatment also were evaluated and reported. The results indicate that percentage of sulfonation is the most important effect, even over thickness. As the sulfonation percentage was increased, better electrical performance (fill factor and power conversion efficiency) was obtained because the sulfonate groups impart a kind of vacancy into the polymer structure, showing comparable energy level to that of conventional poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). In addition, the UV treatment not only cleans the film's surface but also polarizes the polymeric's surface improving the polysulfone performance, which was 24% better, at least, respect to that obtained without UV treatment. The obtained results open the possibility to optimize sulfonated polysulfones that could be used in inverted hybrid perovskite solar cells.
关键词： Hole transport material,Inverted PSC,Thermal treatment,Sulfonated polysulfone,UV treatment
更新于2025-09-16 10:30:52