Crystal Morphology of Hydroxyapatite Modulated by Glutamic Acid at Different Hydrothermal Temperatures

2012 ◽  
Vol 463-464 ◽  
pp. 36-40 ◽  
Author(s):  
Cheng Feng Li ◽  
Xiao Lu Ge ◽  
Shu Guang Liu ◽  
Fei Yu Liu
Keyword(s):  
Glutamic Acid ◽  
Hydrothermal Method ◽  
Formation Mechanism ◽  
Crystal Morphology ◽  
Nucleation And Growth ◽  
Small Concentration ◽  
Crystal Nucleation ◽  
Reaction Solution ◽  
Interfacial Structures

Large-sized hydroxyapatite (HA) crystals with different morphologies, such as whisker-like, tubular and plate-form shape were prepared at different hydrothermal temperatures. Reaction solutions with small concentration of Ca2+, PO43- and OH- ions were used for HA synthesis. Phase identifications and morphological characterizations indicated that HA crystal grew along c axis under the modulation of glutamic acid adsorbent. The formation mechanism was explained according to the interfacial structures between glutamic acid and HA, as well as thermodynamic and kinetic considerations of crystal nucleation and growth. Understanding the evolution of crystal morphology in a specified reaction solution might favor to control the shape of crystals by the hydrothermal method.

Photo Catalytic Properties of Fe-Modified and Magnetic Nanotitanium Prepared by Hydrothermal Method

2013 ◽  
Vol 743-744 ◽  
pp. 843-848
Author(s):  
Ya Ping Zhang ◽  
Qian Qian Zhi ◽  
Lian Qing Yu ◽  
Kai Tuo Dong ◽  
Ri Shan Liu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Hydrothermal Method ◽  
Degradation Rate ◽  
Crystal Morphology ◽  
Separation Efficiency ◽  
Uv Light ◽  
Mercury Lamp ◽  
Photo Catalytic Activity ◽  
Reaction Solution ◽  
Fe Addition

In order to improve the separation efficiency and the circular utilization ratio of the catalyst, the Fe-doped nanotitanium and nanotitanium supported on Fe2O3 carrier was prepared by hydrothermal method. The tetra-butyl titanate and ethanol were used as starting materials to prepare nanotitanium. The results of Fe-doped nanotitanium showed that the doping of iron changed the nanotitanium crystal and crystal morphology. No matter UV-light or mercury lamp 577 nm irradiation, the samples with 0.5 mM Fe addition showed the highest photo catalytic activity, with degradation rate of methyl blue above 95%. The structure, photo catalytic activity and magnetic properties analysis showed that the magnetic nanotitanium met the purpose of separation between the catalyst and reaction solution. The photo catalytic activity of nanotitanium supported on Fe2O3 carrier has respond to visible light. With mercury lamp 577 nm as irradiation source, degradation rate of methylene blue light could reach 63.40%.

scholarly journals Molecular Dynamics Simulations of Crystal Nucleation near Interfaces in Incompatible Polymer Blends

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 347
Author(s):  
Wenlin Zhang ◽  
Lingyi Zou
Keyword(s):  
Molecular Dynamics ◽  
Polymer Blends ◽  
Md Simulations ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Crystalline Order ◽  
Mobile Species ◽  
Deep Supercooling ◽  
Crystallizable Polymer ◽  
Dynamics Simulations

We apply molecular dynamics (MD) simulations to investigate crystal nucleation in incompatible polymer blends under deep supercooling conditions. Simulations of isothermal nucleation are performed for phase-separated blends with different degrees of incompatibility. In weakly segregated blends, slow and incompatible chains in crystallizable polymer domains can significantly hinder the crystal nucleation and growth. When a crystallizable polymer is blended with a more mobile species in interfacial regions, enhanced molecular mobility leads to the fast growth of crystalline order. However, the incubation time remains the same as that in pure samples. By inducing anisotropic alignment near the interfaces of strongly segregated blends, phase separation also promotes crystalline order to grow near interfaces between different polymer domains.

scholarly journals Microwave-Assisted vs. Conventional Hydrothermal Synthesis of MoS2 Nanosheets: Application towards Hydrogen Evolution Reaction

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1040 ◽  
Author(s):  
Getachew Solomon ◽  
Raffaello Mazzaro ◽  
Vittorio Morandi ◽  
Isabella Concina ◽  
Alberto Vomiero
Keyword(s):  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Crystal Morphology ◽  
Synthesis Method ◽  
Synthesis Methods ◽  
Mos2 Nanosheets ◽  
Microwave Assisted

Molybdenum sulfide (MoS2) has emerged as a promising catalyst for hydrogen evolution applications. The synthesis method mainly employed is a conventional hydrothermal method. This method requires a longer time compared to other methods such as microwave synthesis methods. There is a lack of comparison of the two synthesis methods in terms of crystal morphology and its electrochemical activities. In this work, MoS2 nanosheets are synthesized using both hydrothermal (HT-MoS2) and advanced microwave methods (MW-MoS2), their crystal morphology, and catalytical efficiency towards hydrogen evolution reaction (HER) were compared. MoS2 nanosheet is obtained using microwave-assisted synthesis in a very short time (30 min) compared to the 24 h hydrothermal synthesis method. Both methods produce thin and aggregated nanosheets. However, the nanosheets synthesized by the microwave method have a less crumpled structure and smoother edges compared to the hydrothermal method. The as-prepared nanosheets are tested and used as a catalyst for hydrogen evolution results in nearly similar electrocatalytic performance. Experimental results showed that: HT-MoS2 displays a current density of 10 mA/cm2 at overpotential (−280 mV) compared to MW-MoS2 which requires −320 mV to produce a similar current density, suggesting that the HT-MoS2 more active towards hydrogen evolutions reaction.

scholarly journals Crystal nucleation and growth kinetics of NaF in photo-thermo-refractive glass

2013 ◽  
Vol 378 ◽  
pp. 115-120 ◽  
Author(s):  
I. Dyamant ◽  
A.S. Abyzov ◽  
V.M. Fokin ◽  
E.D. Zanotto ◽  
J. Lumeau ◽  
...  
Keyword(s):  
Growth Kinetics ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Kinetics Of

Membrane-protein crystals for neutron diffraction

2018 ◽  
Vol 74 (12) ◽  
pp. 1208-1218 ◽  
Author(s):  
Thomas Lykke-Møller Sørensen ◽  
Samuel John Hjorth-Jensen ◽  
Esko Oksanen ◽  
Jacob Lauwring Andersen ◽  
Claus Olesen ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Neutron Diffraction ◽  
Membrane Protein ◽  
Neutron Source ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Protein Crystals ◽  
Macromolecular Crystallography ◽  
Transport Mechanisms ◽  
Potential Impact

Neutron macromolecular crystallography (NMX) has the potential to provide the experimental input to address unresolved aspects of transport mechanisms and protonation in membrane proteins. However, despite this clear scientific motivation, the practical challenges of obtaining crystals that are large enough to make NMX feasible have so far been prohibitive. Here, the potential impact on feasibility of a more powerful neutron source is reviewed and a strategy for obtaining larger crystals is formulated, exemplified by the calcium-transporting ATPase SERCA1. The challenges encountered at the various steps in the process from crystal nucleation and growth to crystal mounting are explored, and it is demonstrated that NMX-compatible membrane-protein crystals can indeed be obtained.

Synthesis of PZT Disks by a Hydrothermal Method

2012 ◽  
Vol 174-177 ◽  
pp. 592-595
Author(s):  
Lin Lin Yang ◽  
Yong Gang Wang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Method ◽  
Formation Mechanism ◽  
Powder Diffraction ◽  
Self Assembly ◽  
Hydrothermal Process ◽  
X Ray ◽  
Extended Length ◽  
Scanning Electron

The organization of nanostructures across extended length scales is a key challenge in the design of integrated materials with advanced functions. PbZr0.52Ti0.48O3multilayer disks which were constructed by oriented rectangle nanoparticles were easily prepared by a simple surfactant-free hydrothermal process. The as-prepared powders were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that the as-prepared PZT disks were constructed by self-assembly of rectangle nanoparticles by a perfect manner. The formation mechanism of the products was discussed.

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