scholarly journals Effect of Ionic Compounds of Different Valences on the Stability of Titanium Oxide Colloids

2018 ◽  
Vol 2 (3) ◽  
pp. 32 ◽  
Author(s):  
Szabolcs Muráth ◽  
Szilárd Sáringer ◽  
Zoltán Somosi ◽  
István Szilágyi
Keyword(s):  
Titanium Oxide ◽  
Colloidal Stability ◽  
Heterogeneous Systems ◽  
Multivalent Ions ◽  
Aggregation Behaviour ◽  
Ionic Compounds ◽  
Oxide Particles ◽  
Synthetic Routes ◽  
The Stability

Titanium oxide particles of various morphologies have been prepared for applications of scientific or industrial interest in recent decades. Besides development of novel synthetic routes and solid-state characterization of the obtained particles, colloidal stability of titanium oxide dispersions was the focus of numerous research groups due to the high importance of this topic in applications in heterogeneous systems. The influence of dissolved ionic compounds, including monovalent salts, multivalent ions and polyelectrolytes, on the charging and aggregation behaviour of titanium oxide materials of spherical and elongated structures will be discussed in the present review.

Effect of Improved ThO2 Particle Dispersion in Nickel on High-Temperature Strength

1970 ◽  
Vol 28 ◽  
pp. 444-445
Author(s):  
E. R. Kimmel ◽  
H. L. Anthony ◽  
W. Scheithauer
Keyword(s):  
High Temperature ◽  
Metal Matrix ◽  
Oxide Particle ◽  
Oxide Phase ◽  
Dislocation Motion ◽  
Particle Dispersion ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Oxide Particles ◽  
The Stability

The strengthening effect at high temperature produced by a dispersed oxide phase in a metal matrix is seemingly dependent on at least two major contributors: oxide particle size and spatial distribution, and stability of the worked microstructure. These two are strongly interrelated. The stability of the microstructure is produced by polygonization of the worked structure forming low angle cell boundaries which become anchored by the dispersed oxide particles. The effect of the particles on strength is therefore twofold, in that they stabilize the worked microstructure and also hinder dislocation motion during loading.

TEM characterization of Au/Polysilicon interactions

1990 ◽  
Vol 48 (4) ◽  
pp. 650-651
Author(s):  
N. David Theodore ◽  
Leslie H. Allen ◽  
C. Barry Carter ◽  
James W. Mayer
Keyword(s):  
Solid Phase ◽  
Single Crystal Silicon ◽  
Chemical Vapor ◽  
Electrical Contacts ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
Transmission Electron ◽  
Polysilicon Films ◽  
The Stability

Metal/polysilicon investigations contribute to an understanding of issues relevant to the stability of electrical contacts in semiconductor devices. These investigations also contribute to an understanding of Si lateral solid-phase epitactic growth. Metals such as Au, Al and Ag form eutectics with Si. reactions in these metal/polysilicon systems lead to the formation of large-grain silicon. Of these systems, the Al/polysilicon system has been most extensively studied. In this study, the behavior upon thermal annealing of Au/polysilicon bilayers is investigated using cross-section transmission electron microscopy (XTEM). The unique feature of this system is that silicon grain-growth occurs at particularly low temperatures ∽300°C).Gold/polysilicon bilayers were fabricated on thermally oxidized single-crystal silicon substrates. Lowpressure chemical vapor deposition (LPCVD) at 620°C was used to obtain 100 to 400 nm polysilicon films. The surface of the polysilicon was cleaned with a buffered hydrofluoric acid solution. Gold was then thermally evaporated onto the samples.

Host-Guest Interactions on Electrode Surfaces for Immobilization of Molecular Catalysts

2020 ◽  
Author(s):  
Laurent Sévery ◽  
Jacek Szczerbiński ◽  
Mert Taskin ◽  
Isik Tuncay ◽  
Fernanda Brandalise Nunes ◽  
...  
Keyword(s):  
Aqueous Media ◽  
Heterogeneous Systems ◽  
Catalytic Systems ◽  
New Approach ◽  
Molecular Systems ◽  
Electrode Surfaces ◽  
Catalytic Surfaces ◽  
Oxide Electrodes ◽  
The Stability ◽  
Molecular Catalysts

The strategy of anchoring molecular catalysts on electrode surfaces combines the high selectivity and activity of molecular systems with the practicality of heterogeneous systems. The stability of molecular catalysts is, however, far less than that of traditional heterogeneous electrocatalysts, and therefore a method to easily replace anchored molecular catalysts that have degraded could make such electrosynthetic systems more attractive. Here, we apply a non-covalent “click” chemistry approach to reversibly bind molecular electrocatalysts to electrode surfaces via host-guest complexation with surface-anchored cyclodextrins. The host-guest interaction is remarkably strong and allows the flow of electrons between the electrode and the guest catalyst. Electrosynthesis in both organic and aqueous media was demonstrated on metal oxide electrodes, with stability on the order of hours. The catalytic surfaces can be recycled by controlled release of the guest from the host cavities and readsorption of fresh guest. This strategy represents a new approach to practical molecular-based catalytic systems.

Preparation and Characterization of β-glucosidase Films for Stabilization and Handling in Dry Configurations

2020 ◽  
Vol 21 (8) ◽  
pp. 741-747
Author(s):  
Liguang Zhang ◽  
Yanan Shen ◽  
Wenjing Lu ◽  
Lengqiu Guo ◽  
Min Xiang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Protein Function ◽  
Protein Stabilization ◽  
Functional Protein ◽  
Elongation At Break ◽  
Gelatin Films ◽  
The Stability ◽  
And Function ◽  
General Method

Background: Although the stability of proteins is of significance to maintain protein function for therapeutical applications, this remains a challenge. Herein, a general method of preserving protein stability and function was developed using gelatin films. Method: Enzymes immobilized onto films composed of gelatin and Ethylene Glycol (EG) were developed to study their ability to stabilize proteins. As a model functional protein, β-glucosidase was selected. The tensile properties, microstructure, and crystallization behavior of the gelatin films were assessed. Result: Our results indicated that film configurations can preserve the activity of β-glucosidase under rigorous conditions (75% relative humidity and 37°C for 47 days). In both control films and films containing 1.8 % β-glucosidase, tensile strength increased with increased EG content, whilst the elongation at break increased initially, then decreased over time. The presence of β-glucosidase had a negligible influence on tensile strength and elongation at break. Scanning electron-microscopy (SEM) revealed that with increasing EG content or decreasing enzyme concentrations, a denser microstructure was observed. Conclusion: In conclusion, the dry film is a promising candidate to maintain protein stabilization and handling. The configuration is convenient and cheap, and thus applicable to protein storage and transportation processes in the future.

scholarly journals A titanium dioxide–carbon nanotube hybrid to simultaneously achieve the mechanical enhancement of natural rubber and its stability under extreme frictional conditions

2021 ◽  
Vol 2 (7) ◽  
pp. 2408-2418
Author(s):  
Le Wan ◽  
Cong Deng ◽  
Ze-Yong Zhao ◽  
Hai-Bo Zhao ◽  
Yu-Zhong Wang
Keyword(s):  
Titanium Dioxide ◽  
Carbon Nanotube ◽  
Natural Rubber ◽  
Titanium Oxide ◽  
The Stability

Titanium oxide-carbon nanotube hybrids may efficiently promote the stability of nature rubber under extreme frictional conditions.

Characterization of Ultraflat Titanium Oxide Surfaces

2002 ◽  
Vol 14 (2) ◽  
pp. 777-789 ◽  
Author(s):  
Paola Cacciafesta ◽  
Keith R. Hallam ◽  
Caroline A. Oyedepo ◽  
Andrew D. L. Humphris ◽  
Mervyn J. Miles ◽  
...  
Keyword(s):  
Titanium Oxide ◽  
Oxide Surfaces

scholarly journals Stability of Fe-oxide nanoparticles coated with natural organic matter under relevant environmental conditions

2014 ◽  
Vol 70 (12) ◽  
pp. 2040-2046 ◽  
Author(s):  
L. Chekli ◽  
S. Phuntsho ◽  
L. D. Tijing ◽  
J. L. Zhou ◽  
J.-H. Kim ◽  
...  
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Environmental Conditions ◽  
Divalent Cations ◽  
Oxide Nanoparticles ◽  
Fe Oxide ◽  
Coated Nanoparticles ◽  
Aggregation Behaviour ◽  
Physico Chemical ◽  
The Stability

Manufactured nanoparticles (MNPs) are increasingly released into the environment and thus research on their fate and behaviour in complex environmental samples is urgently needed. The fate of MNPs in the aquatic environment will mainly depend on the physico-chemical characteristics of the medium. The presence and concentration of natural organic matter (NOM) will play a significant role on the stability of MNPs by either decreasing or exacerbating the aggregation phenomenon. In this study, we firstly investigated the effect of NOM concentration on the aggregation behaviour of manufactured Fe-oxide nanoparticles. Then, the stability of the coated nanoparticles was assessed under relevant environmental conditions. Flow field-flow fractionation, an emerging method which is gaining popularity in the field of nanotechnology, has been employed and results have been compared to another size-measurement technique to provide increased confidence in the outcomes. Results showed enhanced stability when the nanoparticles are coated with NOM, which was due to electrosteric stabilisation. However, the presence of divalent cations, even at low concentration (i.e. less than 1 mM) was found to induce aggregation of NOM-coated nanoparticles via bridging mechanisms between NOM and Ca2+.

Effect of pH and temperature on the infectivity of human coronavirus 229E

1989 ◽  
Vol 35 (10) ◽  
pp. 972-974 ◽  
Author(s):  
Alain Lamarre ◽  
Pierre J. Talbot
Keyword(s):  
Incubation Period ◽  
Storage Conditions ◽  
Viral Infectivity ◽  
Human Coronavirus ◽  
Virus Growth ◽  
The Stability ◽  
And Storage ◽  
Influence Of Ph ◽  
Human Coronavirus 229E

The stability of human coronavirus 229E infectivity was maximum at pH 6.0 when incubated at either 4 or 33 °C. However, the influence of pH was more pronounced at 33 °C. Viral infectivity was completely lost after a 14-day incubation period at 22, 33, or 37 °C but remained relatively constant at 4 °C for the same length of time. Finally, the infectious titer did not show any significant reduction when subjected to 25 cycles of thawing and freezing. These studies will contribute to optimize virus growth and storage conditions, which will facilitate the molecular characterization of this important pathogen.Key words: coronavirus, pH, temperature, infectivity, human coronavirus.

scholarly journals Characterization of Cocycle Attractors for Nonautonomous Reaction–Diffusion Equations

2016 ◽  
Vol 26 (08) ◽  
pp. 1650135 ◽  
Author(s):  
C. A. Cardoso ◽  
J. A. Langa ◽  
R. Obaya
Keyword(s):  
Chaotic Dynamics ◽  
Linear Part ◽  
Reaction Diffusion ◽  
Positive Cone ◽  
Reaction Diffusion Equations ◽  
Diffusion Equations ◽  
Minimal Set ◽  
Full Characterization ◽  
The Stability

In this paper, we describe in detail the global and cocycle attractors related to nonautonomous scalar differential equations with diffusion. In particular, we investigate reaction–diffusion equations with almost-periodic coefficients. The associated semiflows are strongly monotone which allow us to give a full characterization of the cocycle attractor. We prove that, when the upper Lyapunov exponent associated to the linear part of the equations is positive, the flow is persistent in the positive cone, and we study the stability and the set of continuity points of the section of each minimal set in the global attractor for the skew product semiflow. We illustrate our result with some nontrivial examples showing the richness of the dynamics on this attractor, which in some situations shows internal chaotic dynamics in the Li–Yorke sense. We also include the sublinear and concave cases in order to go further in the characterization of the attractors, including, for instance, a nonautonomous version of the Chafee–Infante equation. In this last case we can show exponentially forward attraction to the cocycle (pullback) attractors in the positive cone of solutions.

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