scholarly journals Synthesis and Morphological Control of VO2 Nanostructures via a One-Step Hydrothermal Method

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 752
Author(s):  
Ozlem Karahan ◽  
Ali Tufani ◽  
Serkan Unal ◽  
I. Burc Misirlioglu ◽  
Yusuf Z. Menceloglu ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Volume Ratio ◽  
Reducing Agent ◽  
Limiting Factor ◽  
Scanning Calorimetry ◽  
High Uniformity ◽  
Specific Morphology ◽  
Annealing Step ◽  
Different Temperatures ◽  
One Step

The morphology of nanostructures is a vital parameter to consider in components comprised of materials exhibiting specific functionalities. The number of process steps and the need for high temperatures can often be a limiting factor when targeting a specific morphology. Here, we demonstrate a repeatable synthesis of different morphologies of a highly crystalline monoclinic phase of vanadium dioxide (VO2(M)) using a one-step hydrothermal method. By adjusting the synthesis parameters, such as pH, temperature, and reducing agent concentration in the precursor, VO2 nanostructures with high uniformity and crystallinity are achieved. Some of these morphologies were obtained via the choice of the reducing agent that allowed us to skip the annealing step. Our results indicate that the morphologies of the nanostructures are very sensitive to the hydrazine hydrate (N2H4.H2O) concentration. Another reducing agent, dodecylamine, was used to achieve well-organized and high-quality VO2(M) nanotubes. Differential scanning calorimetry (DSC) experiments revealed that all samples display the monoclinic-to-tetragonal structural transition (MTST) regardless of the morphology, albeit at different temperatures that can be interpreted as the variations in overheating and undercooling limits. VO2(M) structures with a higher surface to volume ratio exhibit a higher overheating limit than those with low ratios.

Analysis of Ageing Precipitation Behavior of an Aluminum Alloy

2014 ◽  
Vol 488-489 ◽  
pp. 243-247
Author(s):  
Hong Xing Liu ◽  
Jian Bo Zhang ◽  
Qi Ming Liang ◽  
Hai Jun Hu
Keyword(s):  
Electrical Conductivity ◽  
Ageing Time ◽  
Precipitation Behavior ◽  
Scanning Calorimetry ◽  
Exothermic Reactions ◽  
Transmission Electron ◽  
Different Temperatures ◽  
One Step ◽  
Electrical Conductivity Change

The characterization of Al-Cu-Mg-Ag alloy with high Cu:Mg in the process of one-step ageing at the different temperatures has been studied by hardness, electrical conductivity test combining with transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results show that one endothermic and three exothermic reactions are involved in the curve of DSC experiment for a sample quenched from 520°C. Four samples were aged at the different temperatures greater or less than the peak temperatures of the four reactions. Hardness and electrical conductivity change slowly with ageing time at the low temperature and change fast at the high temperature. GP zones at {100} ɑ planes are the main precipitates in the microstructure of the sample aged at 80°C. Ω and θ phases dominant the microstructure of the samples aged at 170°C, 230°C and 280°C. In addition, the size of precipitates increases fast when the sample aged at higher temperatures.

scholarly journals One step synthesis of Ni/Ni(OH)2 nano sheets (NSs) and their application in asymmetric supercapacitors

RSC Advances ◽  
2017 ◽  
Vol 7 (10) ◽  
pp. 5898-5911 ◽  
Author(s):  
Sivasankara Rao Ede ◽  
S. Anantharaj ◽  
K. T. Kumaran ◽  
Soumyaranjan Mishra ◽  
Subrata Kundu
Keyword(s):  
Energy Density ◽  
Specific Capacitance ◽  
Hydrothermal Method ◽  
Maximum Energy ◽  
Reducing Agent ◽  
Asymmetric Supercapacitors ◽  
Facile Hydrothermal Method ◽  
One Step ◽  
Asymmetric Device

Ni/Ni(OH)2 NSs were prepared by a facile hydrothermal method using EtOH as reducing agent. Asymmetric device is fabricated using AC and Ni/Ni(OH)2 NSs as electrodes, with optimized specific capacitance of 62 F g−1 and a maximum energy density of 23.45 W h kg−1.

One-step synthesis of flower-like Cu2O photoelectric materials by hydrothermal method

Solar Energy ◽  
2019 ◽  
Vol 188 ◽  
pp. 265-270 ◽  
Author(s):  
Binxia Yuan ◽  
Xiaobo Liu ◽  
Honghong Fu ◽  
Jianfeng Liu ◽  
Qunzhi Zhu ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
One Step

scholarly journals Influence of Cu on the Improvement of Magnetic Properties and Structure of L10 FePt Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1097
Author(s):  
Luran Zhang ◽  
Xinchen Du ◽  
Hongjie Lu ◽  
Dandan Gao ◽  
Huan Liu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Annealing Temperature ◽  
Reduction Method ◽  
Solid Phase ◽  
Average Particle Size ◽  
Fept Nanoparticles ◽  
Average Particle ◽  
Phase Reduction ◽  
Different Temperatures ◽  
One Step

L10 ordered FePt and FePtCu nanoparticles (NPs) with a good dispersion were successfully fabricated by a simple, green, one-step solid-phase reduction method. Fe (acac)3, Pt (acac)2, and CuO as the precursors were dispersed in NaCl and annealed at different temperatures with an H2-containing atmosphere. As the annealing temperature increased, the chemical order parameter (S), average particle size (D), coercivity (Hc), and saturation magnetization (Ms) of FePt and FePtCu NPs increased and the size distribution range of the particles became wider. The ordered degree, D, Hc, and Ms of FePt NPs were greatly improved by adding 5% Cu. The highest S, D, Hc, and Ms were obtained when FePtCu NPs annealed at 750 °C, which were 0.91, 4.87 nm, 12,200 Oe, and 23.38 emu/g, respectively. The structure and magnetic properties of FePt and FePtCu NPs at different annealing temperatures were investigated and the formation mechanism of FePt and FePtCu NPs were discussed in detail.

One-step hydrothermal method for preparation of Ni/carbon thin film electrodes for efficient electroreduction of imidacloprid

2021 ◽  
Vol 45 (7) ◽  
pp. 3469-3478
Author(s):  
Zongyu Liu ◽  
Ying Tian ◽  
Xuewei Dong ◽  
Xiaohui Zhou ◽  
Xiao Liu ◽  
...  
Keyword(s):  
Thin Film ◽  
Hydrothermal Method ◽  
Removal Efficiency ◽  
Carbon Thin Film ◽  
One Step ◽  
Thin Film Electrodes

A Ni/CTF was used as the cathode for electroreduction of imidacloprid, achieving a 92.1% removal efficiency for the electroreduction of imidacloprid.

Effects of additives on the cure kinetics of vinyl ester pultrusion resins

2021 ◽  
pp. 002199832110015
Author(s):  
Alexander Vedernikov ◽  
Yaroslav Nasonov ◽  
Roman Korotkov ◽  
Sergey Gusev ◽  
Iskander Akhatov ◽  
...  
Keyword(s):  
Vinyl Ester ◽  
Mean Squared Error ◽  
Cure Kinetics ◽  
Zinc Stearate ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Different Temperatures ◽  
Predicted Values ◽  
Kinetics Of ◽  
Final Degree

Pultrusion is a highly efficient composite manufacturing process. To accurately describe pultrusion, an appropriate model of resin cure kinetics is required. In this study, we investigated cure kinetics modeling of a vinyl ester pultrusion resin (Atlac 430) in the presence of aluminum hydroxide (Al(OH)3) and zinc stearate (Zn(C18H35O2)2) as processing additives. Herein, four different resin compositions were studied: neat resin composition, composition with Al(OH)3, composition comprising Zn(C18H35O2)2, and composition containing both Al(OH)3 and Zn(C18H35O2)2. To analyze each composition, we performed differential scanning calorimetry at the heating rates of 5, 7.5, and 10 K/min. To characterize the cure kinetics of Atlac 430, 16 kinetic models were tested, and their performances were compared. The model based on the [Formula: see text]th-order autocatalytic reaction demonstrated the best results, with a 4.5% mean squared error (MSE) between the experimental and predicted data. This study proposes a method to reduce the MSE resulting from the simultaneous melting of Zn(C18H35O2)2. We were able to reduce the MSE by approximately 34%. Numerical simulations conducted at different temperatures and pulling speeds demonstrated a significant influence of resin composition on the pultrusion of a flat laminate profile. Simulation results obtained for the 600 mm long die block at different die temperatures (115, 120, 125, and 130 °C) showed that for a resin with a final degree of cure exceeding 95% at the die exit, the maximum difference between the predicted values of pulling speed for a specified set of compositions may exceed 1.7 times.

A Facile One-Step Surfactant-Free and Low-Temperature Hydrothermal Method to Prepare Uniform 3D Structured Carbonated Apatite Flowers

2009 ◽  
Vol 9 (1) ◽  
pp. 177-181 ◽  
Author(s):  
Kaili Lin ◽  
Jiang Chang ◽  
Yingjie Zhu ◽  
Wei Wu ◽  
Guofeng Cheng ◽  
...  
Keyword(s):  
Low Temperature ◽  
Hydrothermal Method ◽  
Carbonated Apatite ◽  
One Step
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