scholarly journals Intrinsic reconstruction of ice-I surfaces

2020 ◽  
Vol 6 (37) ◽  
pp. eabb7986
Author(s):  
N. Kawakami ◽  
K. Iwata ◽  
A. Shiotari ◽  
Y. Sugimoto
Keyword(s):  
Short Range ◽  
Ice Thickness ◽  
Water Molecules ◽  
Hydrogen Atoms ◽  
Force Microscopy ◽  
Atomic Structures ◽  
Atomic Force ◽  
Physical And Chemical ◽  
The Ideal

Understanding the precise atomic structure of ice surfaces is critical for revealing the mechanisms of physical and chemical phenomena at the surfaces, such as ice growth, melting, and chemical reactions. Nevertheless, no conclusive structure has been established. In this study, noncontact atomic force microscopy was used to address the characterization of the atomic structures of ice Ih(0001) and Ic(111) surfaces. The topmost hydrogen atoms are arranged with a short-range (2 × 2) order, independent of the ice thickness and growth substrates used. The electrostatic repulsion between non–hydrogen-bonded water molecules at the surface causes a reduction in the number of the topmost hydrogen atoms together with a distortion of the ideal honeycomb arrangement of water molecules, leading to a short-range–ordered surface reconstruction.

Investigation of Nanotribological Characterization of Stretched European Hair Using Atomic Force Microscopy

2013 ◽  
Vol 821-822 ◽  
pp. 274-277
Author(s):  
Tao Chen ◽  
Hong Ling Liu ◽  
Wei Dong Yu
Keyword(s):  
Atomic Force Microscopy ◽  
Coefficient Of Friction ◽  
Adhesive Force ◽  
Water Molecules ◽  
Force Microscopy ◽  
Atomic Force ◽  
Friction Measurements ◽  
Stretching Ratio ◽  
Hair Surface

In order to understand the influence of stretching on the nanotribological properties of human hair, the European hair with stretching ratios at 20, 40, 60 and 80% were studied using atomic force microscopy (AFM). The results show that appropriate stretching ratios (40-60%) make the European hair surface smoother and the friction measurements also verify the result. When the stretching ratio is 80%, the European hair has the highest coefficient of friction. The reason is that cuticle damages lead to the local ratchet and collision between AFM tip and the sample obviously increased. With the increase of stretching ratios, the adhesive force of European hair is nonlinear change, which is attributed to the influence of contact area, water molecules absorbed and the amount of polar molecules.

Tribochemical Interactions Between Lubricant Additives and Low Hydrogen Containing DLC Coating Under Boundary Lubrication Conditions

2007 ◽  
Author(s):  
Tabassamul Haque ◽  
Ardian Morina ◽  
Anne Neville
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Characterization ◽  
Analytical Techniques ◽  
Antiwear Additives ◽  
Dlc Coatings ◽  
Force Microscopy ◽  
Dlc Coating ◽  
Atomic Force ◽  
Physical And Chemical

Diamond Like Carbon (DLC) coatings are becoming very popular for automotive tribo-components as they can offer excellent tribological properties resulting in improved fuel economy and reducing dependence on harmful components of existing additives. The tribochemical interactions of low hydrogen containing DLC coating with lubricants, basically customised for ferrous materials, are yet to be well understood. In this work, an experimental study has been performed to understand the synergistic and antagonistic effects of low friction and antiwear additives on a 15 at. % hydrogen containing DLC coating. Surface sensitive analytical techniques, such as atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were used to perform physical and chemical characterization of the tribofilms.

Physical and Chemical Characterization of Atmospheric Aerosols by Atomic Force Microscopy

1999 ◽  
Vol 71 (2) ◽  
pp. 379-383 ◽  
Author(s):  
David W. Lehmpuhl ◽  
Kathryn A. Ramirez-Aguilar ◽  
Amy E. Michel ◽  
Kathy L. Rowlen ◽  
John W. Birks
Keyword(s):  
Atomic Force Microscopy ◽  
Atmospheric Aerosols ◽  
Chemical Characterization ◽  
Force Microscopy ◽  
Atomic Force ◽  
Physical And Chemical Characterization ◽  
Physical And Chemical

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

Stereometric characterization of Dinizia excelsa Ducke wood from Amazon rainforest using atomic force microscopy

2021 ◽  
Author(s):  
Willian Silva Conceição ◽  
Ştefan Ţălu ◽  
Robert Saraiva Matos ◽  
Glenda Quaresma Ramos ◽  
Fidel Guereiro Zayas ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Amazon Rainforest ◽  
Force Microscopy ◽  
Atomic Force ◽  
Dinizia Excelsa

scholarly journals A Universal Model for the Log-Normal Distribution of Elasticity in Polymeric Gels and Its Relevance to Mechanical Signature of Biological Tissues

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 64
Author(s):  
Arnaud Millet
Keyword(s):  
Elastic Modulus ◽  
Normal Distribution ◽  
Biological Tissues ◽  
Force Microscopy ◽  
Polymeric Gels ◽  
Atomic Force ◽  
Clear Explanation ◽  
Log Normal ◽  
Log Normal Distribution

The mechanosensitivity of cells has recently been identified as a process that could greatly influence a cell’s fate. To understand the interaction between cells and their surrounding extracellular matrix, the characterization of the mechanical properties of natural polymeric gels is needed. Atomic force microscopy (AFM) is one of the leading tools used to characterize mechanically biological tissues. It appears that the elasticity (elastic modulus) values obtained by AFM presents a log-normal distribution. Despite its ubiquity, the log-normal distribution concerning the elastic modulus of biological tissues does not have a clear explanation. In this paper, we propose a physical mechanism based on the weak universality of critical exponents in the percolation process leading to gelation. Following this, we discuss the relevance of this model for mechanical signatures of biological tissues.

In Situ Characterization of the Mechanical Behavior of Gecko's Spatulae by Atomic Force Microscopy

2013 ◽  
Vol 22 ◽  
pp. 85-93
Author(s):  
Shuang Yi Liu ◽  
Min Min Tang ◽  
Ai Kah Soh ◽  
Liang Hong
Keyword(s):  
Mechanical Behavior ◽  
Hierarchical Level ◽  
Intrinsic Properties ◽  
In Situ Characterization ◽  
Force Microscopy ◽  
Atomic Force ◽  
Theoretical Predictions ◽  
Multi Mode

In-situ characterization of the mechanical behavior of geckos spatula has been carried out in detail using multi-mode AFM system. Combining successful application of a novel AFM mode, i.e. Harmonix microscopy, the more detail elastic properties of spatula is brought to light. The results obtained show the variation of the mechanical properties on the hierarchical level of a seta, even for the different locations, pad and stalk of the spatula. A model, which has been validated using the existing experimental data and phenomena as well as theoretical predictions for geckos adhesion, crawling and self-cleaning of spatulae, is proposed in this paper. Through contrast of adhesive and craw ability of the gecko on the surfaces with different surface roughness, and measurement of the surface adhesive behaviors of Teflon, the most effective adhesion of the gecko is more dependent on the intrinsic properties of the surface which is adhered.

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