scholarly journals Large Scale Synthesis of Superparamagnetic Face-centered Cubic Co/C Nanocapsules by a Facile Hydrothermal Method and their Microwave Absorbing Properties

2015 ◽  
Vol 18 (4) ◽  
pp. 756-762 ◽  
Author(s):  
Xianguo Liu ◽  
Niandu Wu ◽  
Pingping Zhou ◽  
Nannan Bi ◽  
Siu Wing Or ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Large Scale ◽  
Face Centered Cubic ◽  
Facile Hydrothermal Method ◽  
Microwave Absorbing Properties ◽  
Microwave Absorbing ◽  
Large Scale Synthesis ◽  
Face Centered

Microstructure Characterization of Ag Nanoparticles Prepared by Hydrothermal Method

2012 ◽  
Vol 476-478 ◽  
pp. 1138-1141
Author(s):  
Zhi Qiang Wei ◽  
Qiang Wei ◽  
Li Gang Liu ◽  
Hua Yang ◽  
Xiao Juan Wu
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Hydrothermal Method ◽  
Ag Nanoparticles ◽  
Average Particle Size ◽  
Average Particle ◽  
Face Centered Cubic ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Face Centered

Ag nanoparticles were successfully synthesized by hydrothermal method under the polyol system combined with traces of sodium chloride, Silver nitrate(AgNO3) and polyvinylpyrrolidone (PVP) acted as the silver source and dispersant respectively. The samples by this process were characterized via X-ray powder diffraction (XRD), Brunauer–Emmett–Teller (BET) adsorption equation, transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED) to determine the chemical composition, particle size, crystal structure and morphology. The experiment results indicate that the crystal structure of the samples is face centered cubic (FCC) structure as same as the bulk materials, The specific surface area is 24 m2/g, the particle size distribution ranging from10 to 50 nm, with an average particle size about 26 nm obtained by TEM and confirmed by XRD and BET results.

scholarly journals Metastable–solid phase diagrams derived from polymorphic solidification kinetics

2021 ◽  
Vol 118 (9) ◽  
pp. e2017809118
Author(s):  
Babak Sadigh ◽  
Luis Zepeda-Ruiz ◽  
Jonathan L. Belof
Keyword(s):  
Large Scale ◽  
Solid Phase ◽  
Metastable Phase ◽  
Extensive Study ◽  
The Body ◽  
Face Centered Cubic ◽  
Nonequilibrium Processes ◽  
Solidification Kinetics ◽  
Face Centered ◽  
Dynamics Simulations

Nonequilibrium processes during solidification can lead to kinetic stabilization of metastable crystal phases. A general framework for predicting the solidification conditions that lead to metastable-phase growth is developed and applied to a model face-centered cubic (fcc) metal that undergoes phase transitions to the body-centered cubic (bcc) as well as the hexagonal close-packed phases at high temperatures and pressures. Large-scale molecular dynamics simulations of ultrarapid freezing show that bcc nucleates and grows well outside of the region of its thermodynamic stability. An extensive study of crystal–liquid equilibria confirms that at any given pressure, there is a multitude of metastable solid phases that can coexist with the liquid phase. We define for every crystal phase, a solid cluster in liquid (SCL) basin, which contains all solid clusters of that phase coexisting with the liquid. A rigorous methodology is developed that allows for practical calculations of nucleation rates into arbitrary SCL basins from the undercooled melt. It is demonstrated that at large undercoolings, phase selections made during the nucleation stage can be undone by kinetic instabilities amid the growth stage. On these bases, a solidification–kinetic phase diagram is drawn for the model fcc system that delimits the conditions for macroscopic grains of metastable bcc phase to grow from the melt. We conclude with a study of unconventional interfacial kinetics at special interfaces, which can bring about heterogeneous multiphase crystal growth. A first-order interfacial phase transformation accompanied by a growth-mode transition is examined.

Molecular Dynamics Simulations of Nanocrystalline Nickel and Copper Revealing Different Failure Model of FCC Metals

2009 ◽  
Vol 633-634 ◽  
pp. 31-38
Author(s):  
Ajing Cao
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Grain Boundaries ◽  
Large Scale ◽  
Uniaxial Tensile ◽  
Face Centered Cubic ◽  
Triple Junctions ◽  
Fcc Metals ◽  
Face Centered ◽  
Dynamics Simulations

We have previously reported that the fracture behavior of nanocrystalline (NC) Ni is via the nucleation and coalescence of nano-voids at grain boundaries and triple junctions, resulting in intergranular failure mode. Here we show in large-scale molecular dynamics simulations that partial-dislocation-mediated plasticity is dominant in NC Cu with grain size as small as ~ 10 nanometers. The simulated results show that NC Cu can accommodate large plastic strains without cracking or creating damage in the grain interior or grain boundaries, revealing their intrinsic ductile properties compared with NC Ni. These results point out different failure mechanisms of the two face-centered-cubic (FCC) metals subject to uniaxial tensile loading. The insight gained in the computational experiments could explain the good plasticity found in NC Cu not seen in Ni so far.

scholarly journals A new strategy for large-scale synthesis of Na0.5Bi0.5TiO3 nanowires and their application in piezocatalytic degradation

2021 ◽  
Author(s):  
Rui Huang ◽  
Jiang Wu ◽  
Enzhu Lin ◽  
Zihan Kang ◽  
Ni Qin ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Organic Pollutants ◽  
Large Scale ◽  
New Strategy ◽  
Large Scale Synthesis

Na0.5Bi0.5TiO3 nanowires prepared by the template hydrothermal method exhibited excellent piezocatalytic activity in the degradation of organic pollutants.

A Method for Lamping Atoms into Particles in Particle Dynamic Method

2011 ◽  
Vol 295-297 ◽  
pp. 1029-1037
Author(s):  
Jie Wei ◽  
Yu Feng Nie ◽  
Li Cai
Keyword(s):  
Crystal Structure ◽  
Mass Distribution ◽  
Topological Structure ◽  
Large Scale ◽  
Small Scale ◽  
Particle Dynamic ◽  
Face Centered Cubic ◽  
Cubic Crystal ◽  
Theoretical Support ◽  
Face Centered

Generalized particle dynamics method (GP) is a kind of new multi-scale analysis approach which relates various scales naturally through cohering small scale lattice to large-scale lattice. In this paper, a method named nearby condensation method is proposed to lump small scale lattice to large-scale lattice keeping topology structure and mass distribution. The method provides a theoretical support to the GP method. It is indicated that, after cohesion BCC (Body-Centered Cubic) crystal structure possessed the same topological structure and mass distribution, and FCC (Face-centered cubic) crystal structure possessed the same topological structure, but the mass distribution gradually converges to a steady state.

Large-Scale Synthesis of Large-Sized Monodispersed Iron Oxide Nanoeggs

2014 ◽  
Vol 692 ◽  
pp. 206-209
Author(s):  
Xiao Li Liu ◽  
Jun Ding
Keyword(s):  
Iron Oxide ◽  
Single Crystal ◽  
Hydrothermal Method ◽  
Large Scale ◽  
Chemical Reduction ◽  
Ferric Ions ◽  
Uniform Size ◽  
Size And Shape ◽  
Large Scale Synthesis

Single-crystal hematite (α-Fe2O3) nanoeggs are firstly synthesized using an anion-assisted hydrothermal method. By adjusting the ratios of phosphate to ferric ions, we are able to produce an egg-like nanostructure. And then α-Fe2O3nanoeggs are converted to magnetite (Fe3O4) by a chemical reduction while preserving the same morphology. The characterizations of Fe3O4nanoeggs indicate Fe3O4nanoeggs with uniform size and shape are successful synthesized. Our results provide an easily scaled-up method for preparing tailor-made large-sized iron oxide nanoeggs that could meet the demands of a variety of applications.

scholarly journals Recreating Ductility-Dip Cracking via Gleeble®-Based Welding Simulation

2021 ◽  
Vol 100 (01) ◽  
pp. 27-39
Author(s):  
SAMUEL LUTHER ◽  
◽  
BOIAN ALEXANDROV
Keyword(s):  
Elevated Temperature ◽  
Nuclear Power ◽  
Large Scale ◽  
Mechanical Energy ◽  
Austenitic Stainless Steels ◽  
Face Centered Cubic ◽  
Experimental Procedure ◽  
Thermomechanical Cycling ◽  
310 Stainless Steel ◽  
Face Centered

Face-centered cubic alloys, such as nickel-based alloys and austenitic stainless steels, are important to many industries, notably nuclear power generation and petrochemical. These alloys are prone to ductility-dip cracking (DDC), an inter-mediate-temperature, solid-state cracking phenomenon. They experience an abnormal elevated-temperature ductility loss, which leads to cracking upon applying sufficient restraint. A unified mechanism for DDC has been elusive. To learn more about DDC, an experimental procedure has been designed and evaluated for use in future studies. It is a thermomechanical test that replicates welding conditions via simulated strain ratcheting (SSR) using the Gleeble thermomechanical simulator. This study evaluates SSR and aims to establish the procedure is reproducible and adequately optimized for producing DDC. A design of experiments was created with four alloys tested at varying preloads, elevated temperature strains, and a number of thermomechanical cycles. Mechanical energy imposed within the DDC temperature range was used for quantification of the effect of thermomechanical cycling on the DDC response. The materials tested were 310 stainless steel and Nickel 201 base metals as well as nickel-based filler metals 52M and 52MSS. The SSR successfully recreated DDC while maintaining higher fidelity to actual production conditions than past laboratory tests and offered a more controlled environment than large-scale weld tests. Therefore, the SSR will provide a viable experimental procedure for learning more about the DDC mechanism.

Hydrothermal Synthesis of Flower-Like Silver Nanoplate Micro-Assemblies in High Yields

2011 ◽  
Vol 675-677 ◽  
pp. 299-302 ◽  
Author(s):  
Xin He ◽  
Su Yu Yang ◽  
Mei Zhang
Keyword(s):  
Ascorbic Acid ◽  
Vinyl Pyrrolidone ◽  
Molar Ratio ◽  
Face Centered Cubic ◽  
Facile Hydrothermal Method ◽  
Cubic Structure ◽  
Face Centered ◽  
Poly Vinyl Pyrrolidone ◽  
High Yields ◽  
Average Size

We demonstrated the fabrication of the flower-like silver nanoplate micro-assemblies in high yields by a facile hydrothermal method. This novel nanostructure was synthesized in the presence of poly (vinyl pyrrolidone) (PVP) and ascorbic acid (AsA) at 150 °C for 10 h. The microassemblies with average size of 1~2 μm are consisted of several uniform nanoplates and show face centered cubic structure. The effects of the concentration of reactants, molar ratio of silver nitrate to ascorbic acid on the formation of the flower-like silver micro-assemblies were also presented.

A Simple Hydrothermal Method for the Large-Scale Synthesis of Single-Crystal Potassium Tungsten Bronze Nanowires

2006 ◽  
Vol 12 (29) ◽  
pp. 7717-7723 ◽  
Author(s):  
Zhanjun Gu ◽  
Ying Ma ◽  
Tianyou Zhai ◽  
Bifen Gao ◽  
Wensheng Yang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Hydrothermal Method ◽  
Large Scale ◽  
Tungsten Bronze ◽  
Simple Hydrothermal Method ◽  
Large Scale Synthesis
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