The reaction sequence and microstructure evolution of an MgB2 layer during ex situ annealing of amorphous boron film

2004 ◽  
Vol 19 (2) ◽  
pp. 409-412 ◽  
Author(s):  
Hyun-Mi Kim ◽  
Sung-Soo Yim ◽  
Ki-Bum Kim ◽  
Dae-Hwan Kang ◽  
Seung-Hyun Moon ◽  
...  
Keyword(s):  
Thin Layer ◽  
Microstructure Evolution ◽  
Growth Process ◽  
Nucleation And Growth ◽  
The Other ◽  
Ex Situ ◽  
Amorphous Boron ◽  
Reaction Sequence ◽  
Initial Stage ◽  
Polycrystalline Form

The reaction sequence and microstructure evolution of a crystalline MgB2 layer were examined during ex situ annealing of evaporated amorphous boron (a-B) with Mg vapor. Mg was found to migrate rapidly into the a-B layer in the initial stage of reaction with a uniform concentration of about 12 at.%. A thin layer of crystalline MgO was observed at the interface between a-B and the Al2O3 substrate. It was identified that an MgB2 layer started to form at the surface by the nucleation and growth process in polycrystalline form. It appears that there exists two distinct growth fronts in the MgB2 layer: one lying at the surface and the other lying at the interface between the MgB2 layer and the a-B. The microstructural evolution of this layer showed significant differences depending on the location of these two growth fronts.

Fractal simulation of thin film nucleation growth process using a diffusion-limited aggregation model

2018 ◽  
Vol 32 (33) ◽  
pp. 1850408 ◽  
Author(s):  
Min Zhang ◽  
Chaoyong Deng
Keyword(s):  
Fractal Dimension ◽  
Growth Process ◽  
Film Growth ◽  
Nucleation And Growth ◽  
Diffusion Limited Aggregation ◽  
Diffusion Limited ◽  
Initial Stage ◽  
Initial Nucleation ◽  
Fractal Simulation ◽  
Film Nucleation

In order to study the initial nucleation and growth process of the films, a two-dimensional (2D) DLA model was established, and fractal dimension was calculated by sandbox method. Compared with the experimental results, the model can well characterize the morphology of nucleation and growth in the initial stage of film growth. In addition to the number of particles and deposition probability involved in other studies, the size of substrate and the location of central particles are also considered in this work. The growth morphology, fractal dimension and the number of simulated steps are presented in this paper.

scholarly journals Biopolymer colloids for controlling and templating inorganic synthesis

2014 ◽  
Vol 5 ◽  
pp. 2129-2138 ◽  
Author(s):  
Laura C Preiss ◽  
Katharina Landfester ◽  
Rafael Muñoz-Espí
Keyword(s):  
Nucleation And Growth ◽  
Inorganic Materials ◽  
The Other ◽  
Shell Structures ◽  
Ex Situ ◽  
Inorganic Synthesis ◽  
Wide Range ◽  
Synthetic Approaches ◽  
Soft Templates

Biopolymers and biopolymer colloids can act as controlling agents and templates not only in many processes in nature, but also in a wide range of synthetic approaches. Inorganic materials can be either synthesized ex situ and later incorporated into a biopolymer structuring matrix or grown in situ in the presence of biopolymers. In this review, we focus mainly on the latter case and distinguish between the following possibilities: (i) biopolymers as controlling agents of nucleation and growth of inorganic materials; (ii) biopolymers as supports, either as molecular supports or as carrier particles acting as cores of core–shell structures; and (iii) so-called “soft templates”, which include on one hand stabilized droplets, micelles, and vesicles, and on the other hand continuous scaffolds generated by gelling biopolymers.

Ni cluster nucleation and growth on the anatase TiO2(101) surface: a density functional theory study

RSC Advances ◽  
2015 ◽  
Vol 5 (21) ◽  
pp. 16582-16591 ◽  
Author(s):  
Yanxin Wang ◽  
Yan Su ◽  
Mingyuan Zhu ◽  
Lihua Kang
Keyword(s):  
Density Functional Theory ◽  
Driving Force ◽  
Cluster Size ◽  
Density Functional ◽  
Growth Process ◽  
Nucleation And Growth ◽  
Anatase Tio2 ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Initial Stage

The Ni–TiO2 interaction is the main driving force at the initial stage of Ni nucleation. The Ni–Ni interaction begins to control the growth process as the cluster size gets larger.

Fundamental Research into Thin Films in a Developing Country

1972 ◽  
Vol 30 ◽  
pp. 500-501
Author(s):  
J.A. Eades ◽  
E. Grünbaum
Keyword(s):  
Thin Films ◽  
Growth Process ◽  
Empirical Process ◽  
Nucleation And Growth ◽  
Research Groups ◽  
Film Research ◽  
Fundamental Research ◽  
Controlled Deposition ◽  
The One ◽  
The University

In the last decade and a half, thin film research, particularly research into problems associated with epitaxy, has developed from a simple empirical process of determining the conditions for epitaxy into a complex analytical and experimental study of the nucleation and growth process on the one hand and a technology of very great importance on the other. During this period the thin films group of the University of Chile has studied the epitaxy of metals on metal and insulating substrates. The development of the group, one of the first research groups in physics to be established in the country, has parallelled the increasing complexity of the field.The elaborate techniques and equipment now needed for research into thin films may be illustrated by considering the plant and facilities of this group as characteristic of a good system for the controlled deposition and study of thin films.

Which One of Two Ectopic Mandibular Canines will erupt to a Normal Position in the Dental Arch

2018 ◽  
Author(s):  
M Svanholt ◽  
P Svanholt ◽  
Inger Kjær
Keyword(s):  
The Other ◽  
Mixed Dentition ◽  
Dental Arch ◽  
Horizontal Position ◽  
Normal Position ◽  
Initial Stage ◽  
Mandibular Canine ◽  
The One

The purpose of this paper is to demonstrate 4 cases with bi-lateral ectopic mandibular canines and to demonstrate in each case which one of the two canines erupted to a normal position in the dental arch. The canines are observed from Orthopantomograms from 4 children (aged 8-13 years of age) in the mixed dentitions stages. Of these children 2 were males and 2 were females. From each child there was between 3-5 Orthopantomograms. These were observed over 3-4 years period. In each of the 4 cases with bi-lateral ectopia of the mandibular canines the one mandibular canine erupted into a normal position, while the other one declined into a horizontal position during the mixed dentition period. These 4 cases demonstrated that the inclination of the canines were important to observe and diagnose from the initial stage (first ortopantomogram). The cases presented, demonstrated that the unsuccessfully erupted canines ending in a horizontal position, were the canines which inclined slightly more that the contra lateral canine already from the initial stage.

Peculiarities of the neck growth process during initial stage of spark-plasma, microwave and conventional sintering of WC spheres

2012 ◽  
Vol 523 ◽  
pp. 1-10 ◽  
Author(s):  
Dmytro Demirskyi ◽  
Hanna Borodianska ◽  
Dinesh Agrawal ◽  
Andrey Ragulya ◽  
Yoshio Sakka ◽  
...  
Keyword(s):  
Growth Process ◽  
Neck Growth ◽  
Initial Stage ◽  
Conventional Sintering ◽  
Spark Plasma ◽  
Plasma Microwave

Significance of analysis of the mechanism of fingermarks formation, sizes and location – casework examples

2018 ◽  
Vol 301 ◽  
pp. 44-52
Author(s):  
Tomasz Kowalski ◽  
Keyword(s):  
Significant Role ◽  
Special Interest ◽  
The Other ◽  
Fatal Accident ◽  
Preliminary Stage ◽  
Additional Information ◽  
Expert Opinions ◽  
First Case ◽  
Initial Stage

The aim of the article to present the role of analysing the manner of generating fingermarks in the investigative proceedings. These examinations are based on the analysis of the location of the marks on a given background and aim at providing the requesting party additional information about the circumstances of the investigated incident. The Author refers to two unusual cases, in which Voivodeship Police Command Forensic Laboratory issued expert opinions in the area of fingerprint identification. In the first case, at the initial stage of the proceedings the circumstances and recovered evidential fingermarks indicated a fatal accident or manslaughter by means of a firearm. In the other case at the preliminary stage recovered evidence did not allow identification of the perpetrator due to incorrectly selected exhibits. These cases would not be off special interest to us without the significant role of proper recovering of fingermarks and their analysis in a broader context than just identification.

Nucleation and growth of Al2O3/metal composites by oxidation of aluminum alloys

1991 ◽  
Vol 6 (9) ◽  
pp. 1964-1981 ◽  
Author(s):  
O. Salas ◽  
H. Ni ◽  
V. Jayaram ◽  
K.C. Vlach ◽  
C.G. Levi ◽  
...  
Keyword(s):  
Growth Process ◽  
Nucleation And Growth ◽  
Al Alloy ◽  
Oxide Growth ◽  
Spinel Layer ◽  
Initial Oxidation ◽  
Temperature Oxidation ◽  
Continuous Formation ◽  
Initial Event ◽  
Al Composite

The nucleation and growth mechanisms during high temperature oxidation of liquid Al−3% Mg and Al−3% Mg−3% Si alloys were studied with the aim of enhancing our understanding of a new composite fabrication process. The typical oxidation sequence consists of an initial event of rapid but brief oxidation, followed by an incubation period of limited oxide growth after which bulk Al2O3/Al composite forms. A duplex oxide layer, MgO (upper) and MgAl2O4 (lower), forms on the alloy surface during initial oxidation and incubation. The spinel layer remains next to the liquid alloy during bulk oxide growth and is the eventual repository for most of the magnesium in the original alloy. Metal microchannels developed during incubation continuously supply alloy through the composite to the reaction interface. During the growth process, a layered structure exists at the upper extremity of the composite, consisting of MgO at the top surface, MgAl2O4 (probably discontinuous), Al alloy, and finally the bulk Al2O3 composite containing microchannels of the alloy. The bulk oxide growth mechanism appears to involve continuous formation and dissolution of the Mg-rich oxides at the surface, diffusion of oxygen through the underlying liquid metal, and epitaxial growth of Al2O3 on the existing composite body. The roles of Mg and Si in the composite growth process are discussed.

Ultrastructural features of the sensori-motor cortex of the primate

1979 ◽  
Vol 285 (1006) ◽  
pp. 123-139 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Motor Cortex ◽  
Thin Layer ◽  
Liquid Helium ◽  
Thermal Insulation ◽  
Solid Surfaces ◽  
The Other ◽  
Experimental Chamber ◽  
Short Discussion ◽  
Inside Wall

cooled to 2°K or lower. Rollin (1936) found that the thermal insulation of vessels containing liquid helium was much worse below than above the A point. He explained his observation by assuming the existence of a thin layer of liquid helium on the inside wall of the connecting tube, and thought it probable that the change in thermal conductivity of this film at the A point gave rise to the anomalous effects observed. As the result of more recent (unpublished) experiments Rollin and Simon* have put forward the other explanation that the film creeps up the tube and evaporates eventually. It is obvious that all these phenomena may have a common explanation and it was the object of the experiments described in this paper and the following paper to investigate the behaviour of He 11 in contact with solid surfaces systematically. The phenomena had to be investigated from various aspects and this made experiments necessary which varied in purpose and character to some extent. For simplicity’s sake we will therefore give, together with the description of each experiment, a short discussion and summarize at the end of the second paper all results in a general discussion on the whole phenomenon. All experiments were carried out in the same cryostat; and for different experiments only the experimental chamber and the experimental arrangement in it were altered.

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