High resolution nanoscale chemical analysis of bitumen surface microstructures

AbstractSurface microstructures of bitumen are key sites in atmospheric photo-oxidation leading to changes in the mechanical properties and finally resulting in cracking and rutting of the material. Investigations at the nanoscale remain challenging. Conventional combination of optical microscopy and spectroscopy cannot resolve the submicrostructures due to the Abbe restriction. For the first time, we report here respective surface domains, namely catana, peri and para phases, correlated to distinct molecules using combinations of atomic force microscopy with infrared spectroscopy and with correlative time of flight—secondary ion mass spectrometry. Chemical heterogeneities on the surface lead to selective oxidation due to their varying susceptibility to photo-oxidation. It was found, that highly oxidized compounds, are preferentially situated in the para phase, which are mainly asphaltenes, emphasising their high oxidizability. This is an impressive example how chemical visualization allows elucidation of the submicrostructures and explains their response to reactive oxygen species from the atmosphere.

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Epitaxial Growth of Single Crystalline Ge Films on GaAs Substrates for CMOS Device Integration

MRS Proceedings ◽

10.1557/proc-1068-c07-02 ◽

2008 ◽

Vol 1068 ◽

Author(s):

Hock-Chun Chin ◽

Ming Zhu ◽

Ganesh Samudra ◽

Yee-Chia Yeo

Keyword(s):

High Resolution ◽

Epitaxial Growth ◽

Secondary Ion Mass Spectrometry ◽

Chemical Vapor ◽

X Ray Diffraction ◽

Gate Stack ◽

Force Microscopy ◽

Atomic Force ◽

Transmission Electron ◽

First Time

ABSTRACTWe report a novel chemical vapor deposition (CVD) process for epitaxial growth of Ge film on GaAs substrate. The resultant layer exhibits device level quality, as shown by high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, high-resolution X-ray diffraction (HRXRD). In addition, atomic force microscopy (AFM) scanning indicates low RMS surface roughness of 5 Å. Secondary ion mass spectrometry (SIMS) reveals negligible out-diffusion of Ga and As into the Ge epilayer. By employing silane passivation, Ge p-MOSFET with TaN/HfO2 gate stack was fabricated on Ge/GaAs heterostructure for the first time, showing excellent output and pinch-off characteristics. A GaAs channel n-MOSFET was also fabricated, using similar SiH4 treatment during gate stack formation. These results reveal a potential solution to integrate Ge p-channel and GaAs n-channel MOSFET for advanced CMOS applications.

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Depth Profile Analysis of Thin Oxide Layers on Polycrystalline Fe–Cr

Microscopy and Microanalysis ◽

10.1017/s1431927619015319 ◽

2020 ◽

Vol 26 (1) ◽

pp. 112-119

Author(s):

Gerrit Zijlstra ◽

Tomáš Šamořil ◽

Hana Tesařová ◽

Václav Ocelík ◽

Jeff Th. M. De Hosson

Keyword(s):

Oxide Layer ◽

Grain Orientation ◽

Secondary Ion Mass Spectrometry ◽

Profile Analysis ◽

Oxide Layers ◽

Force Microscopy ◽

Atomic Force ◽

Thin Oxide ◽

Oxidation In Air ◽

First Time

AbstractSurfaces of polycrystalline ferritic Fe–Cr steel with grain sizes of about 13 µm in diameter were investigated with surface sensitive techniques. Thin oxide layers, with a maximum thickness of about 100 nm, were grown by oxidation in air at temperatures up to 450°C and were subsequently characterized using time-of-flight secondary ion mass spectrometry (TOF-SIMS) and atomic force microscopy. Correlative microscopy was applied, which allows for element-specific depth profiles on selected grains with a particular crystal orientation. A strong correlation between the grain orientation and the thickness of the oxide layer was found. The sequence in the oxidation growth rate of ferritic Fe–Cr steel crystal planes is found to be {011} > {111} > {001}, which is unexpectedly opposed to known Fe-based systems. Moreover, for the first time, the Cr/Fe ratio throughout the oxide layer has been determined per grain orientation. A clear order from high to low of {001} > {111} > {011} was detected.

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Preparation and Characterization of Chitosan-Casein Phosphopeptides Biocomposite Coatings on the Medical Titanium Alloy

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.480-481.1065 ◽

2011 ◽

Vol 480-481 ◽

pp. 1065-1069

Author(s):

Bin Liu ◽

Lin Wang ◽

Yin Zhong Bu ◽

Sheng Rong Yang ◽

Jin Qing Wang

Keyword(s):

Photoelectron Spectroscopy ◽

Attenuated Total Reflectance ◽

Ti Alloy ◽

Force Microscopy ◽

Implant Materials ◽

Atomic Force ◽

Casein Phosphopeptides ◽

Potential Applications ◽

First Time

Titanium (Ti) and its alloys have been applied in orthopedics as one of the most popular biomedical metallic implant materials. In this work, to enhance the bioactivity, the surface of Ti alloy pre-modified by silane coupling agent and glutaraldehyde was covalently grafted with chitosan (CS) via biochemical multistep self-assembled method. Then, for the first time, the achieved surface was further immobilized with casein phosphopeptides (CPP), which are one group of bioactive peptides released from caseins in the digestive tract and can facilitate the calcium adsorption and usage, to form CS-CPP biocomposite coatings. The structure and composition of the fabricated coatings were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and atomic force microscopy (AFM). As the experimental results indicated, multi-step assembly was successfully performed, and the CS and CPP were assembled onto the Ti alloy surface orderly. It is anticipated that the Ti alloys modified by CS-CPP biocomposite coatings will find potential applications as implant materials in biomedical fields.

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Microwave Spectroscopic Detection of Human Hsp70 Protein on Annealed Gold Nanostructures on ITO Glass Strips

Biosensors ◽

10.3390/bios8040118 ◽

2018 ◽

Vol 8 (4) ◽

pp. 118

Author(s):

Rodica Ionescu ◽

Raphael Selon ◽

Nicolas Pocholle ◽

Lan Zhou ◽

Anna Rumyantseva ◽

...

Keyword(s):

Indium Tin Oxide ◽

Stress Disorders ◽

Force Microscopy ◽

Glass Substrates ◽

Conductive Glass ◽

Hsp70 Protein ◽

Atomic Force ◽

Ito Glass ◽

First Time ◽

Human Heat Shock Protein

Conductive indium-tin oxide (ITO) and non-conductive glass substrates were successfully modified with embedded gold nanoparticles (AuNPs) formed by controlled thermal annealing at 550 °C for 8 h in a preselected oven. The authors characterized the formation of AuNPs using two microscopic techniques: scanning electron microscopy (SEM) and atomic force microscopy (AFM). The analytical performances of the nanostructured-glasses were compared regarding biosensing of Hsp70, an ATP-driven molecular chaperone. In this work, the human heat-shock protein (Hsp70), was chosen as a model biomarker of body stress disorders for microwave spectroscopic investigations. It was found that microwave screening at 4 GHz allowed for the first time the detection of 12 ng/µL/cm2 of Hsp70.

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Marrying Medicine and Materials: Artemisinin (Qinghaosu) Particle is Soft Enough for Scratching Hard SiC Wafer in Water

ScienceOpen Research ◽

10.14293/s2199-1006.1.sor-matsci.amnmzs.v1 ◽

2016 ◽

Author(s):

Yu-rong Zhu ◽

Dan Zhang ◽

Yang Gan ◽

Fei-hu Zhang

Keyword(s):

Pure Water ◽

High Hardness ◽

Underlying Mechanism ◽

Molecular Solids ◽

High Brightness ◽

Force Microscopy ◽

Atomic Force ◽

Chemical Inertness ◽

Sic Wafer ◽

First Time

<p>Silicon carbide (SiC) single crystals, along with sapphire and silicon, are one of most important substrates for high-brightness LED fabrications. Owing to extremely high hardness (Mohs’ scale of 9.5) and chemical inertness, the polishing rate of SiC with conventional chemical mechanical polishing (CMP) methods is not high, and surface scratches are also inevitable because of using slurry containing hard abrasives such as silica particles. Here artemisinin (Qinghaosu) crystals, very soft molecular solids, were found, for the first time to the best of our knowledge, to effectively polish SiC wafers even in pure water as demonstrated by proof-of-concept scratching experiments using atomic force microscopy (AFM). The underlying mechanism is attributed to activated oxidation of SiC by mechanically released reactive ·OH free radicals from the endoperoxide bridges. The preliminary results reported here have important implications for developing novel alternative green and scratch-free polishing methods for hard-brittle substrates including SiC and others.</p>

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Flotation Behavior of Diatomite and Albite Using Dodecylamine as a Collector

Minerals ◽

10.3390/min8090371 ◽

2018 ◽

Vol 8 (9) ◽

pp. 371 ◽

Cited By ~ 1

Author(s):

Ying Gao ◽

Yuexin Han ◽

Wenbo Li

Keyword(s):

Unit Area ◽

Alkaline Ph ◽

Force Microscopy ◽

Atomic Force ◽

Mineral Flotation ◽

Alkaline Conditions ◽

Negative Surface ◽

Negative Surface Charge ◽

Ph Range ◽

First Time

The flotation behaviors of diatomite and albite using dodecylamine (DDA) as a collector were investigated and compared. The pure mineral flotation results indicate that the flotability difference between albite and diatomite is above 87% at pH 5.5 to 10.5. The recovery of albite improves with increasing DDA dosage at pH 5.5 to 10.5. In the same pH range, diatomite has weaker flotability than albite, particularly in alkaline pH pulp. Zeta potential measurements indicate that diatomite has a higher negative surface charge than albite at pH 7 to 12, DDA interacts strongly with albite and weakly with diatomite. Thus, DDA preferentially absorbs on albite surface rather than diatomite under alkaline conditions. Fourier transform infrared spectra (FTIR) indicate that the amount of DDA adsorbed to albite is greater than that adsorbed to diatomite, under the same conditions. The adsorption of DDA on the surface of diatomite is investigated by using atomic force microscopy (AFM) for the first time. The adsorption of the collector DDA on the surface of albite per unit area is greater than that on diatomite. This accounts for the lower recovery of diatomite than that of albite.

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Transparent Conducting Indium-Tin-Oxide Thin Film with Extremely Flatted Surface

MRS Proceedings ◽

10.1557/proc-666-f3.15 ◽

2001 ◽

Vol 666 ◽

Author(s):

Hiromichi Ohta ◽

Masahiro Orita ◽

Masahiro Hirano ◽

Hideo Hosono

Keyword(s):

Thin Film ◽

Tin Oxide ◽

Indium Tin Oxide ◽

Film Growth ◽

Oxide Thin Film ◽

Force Microscopy ◽

Atomic Force ◽

Out Of Plane ◽

Key Factor ◽

Surface Microstructures

ABSTRACTIndium-tin-oxide films were grown hetero-epitaxially on YSZ surface at a substrate temperature of 900 °C, and their surface microstructures were observed by using atomic force microscopy. ITO films grown on (111) surface of YSZ exhibited very high crystal quality; full width at half maximum of out-of-plane rocking curve was 54 second. The ITO was grown spirally, with flat terraces and steps corresponding to (222) plane spacing of 0.29 nm. Oxygen pressure during film growth is another key factor to obtain atomically flat surfaced ITO thin film.

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First identification of nanoparticles on thorax, abdomen and wings of the worker bee Apis dorsata Fabricius

Journal of Apicultural Science ◽

10.1515/jas-2016-0008 ◽

2016 ◽

Vol 60 (1) ◽

pp. 87-96

Author(s):

Atanu Bhattacharyya ◽

Shashidhar Viraktamath ◽

Fani Hatjina ◽

Santanu Bhattacharyya ◽

Bhaktibhavana Rajankar ◽

...

Keyword(s):

Electron Microscopy ◽

Average Diameter ◽

The Body ◽

Apis Dorsata ◽

Force Microscopy ◽

Atomic Force ◽

Transmission Electron ◽

Calcium Phosphate Nanoparticles ◽

First Time

Abstract The presence of nanoparticles on the body of the honeybee Apis dorsata Fabricius, was investigated for the first time to better understand the bee’s behaviour. These have been observed by using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and confirmed by Atomic Force Microscopy (AFM). Our study clearly denotes that the Indian rock honey bee Apis dorsata possess calcium silicate and calcium phosphate nanoparticles on its body surface of 5-50 nm in diameter. In particular, the nanoparticles on the abdomen and thorax of A. dorsata have an average diameter of about 10 nanometers and they are smaller than those found on wings of the same bees which are about 20 nanometers. The nanoparticles found are different of the ones previously observed on honey bees or other insects. The origin and role of these natural nanoparticles on the body of the Indian rock bee need to be to be further investigated; more research in the subject might raise important aspects in relation to the conservation of these unique pollinators.

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Latest developments for microstructural and chemical characterization of diffusion bonding in superplastic 8090 Al–Li alloys

Journal of Materials Research ◽

10.1557/jmr.1996.0009 ◽

1996 ◽

Vol 11 (1) ◽

pp. 63-71 ◽

Cited By ~ 3

Author(s):

A. Ureña ◽

J. M. Gómez de Salazar ◽

J. J. Martín ◽

J. Quiñones

Keyword(s):

Surface Characterization ◽

Secondary Ion Mass Spectrometry ◽

Mixed Oxides ◽

Chemical Characterization ◽

Bond Line ◽

Force Microscopy ◽

Atomic Force ◽

Bond Interface ◽

Secondary Ion

This paper describes a new application of two complementary surface characterization techniques to study solid-state bonding in an Al–Li alloy. Through the two mentioned techniques, Atomic Force Microscopy (AFM) and Secondary Ion Mass Spectrometry (SIMS), important findings about what takes place in the bond interface have been determined. These findings enclose both the formation of discontinuous mixed oxides and the evolution of Li through the bond line and into theadjacent diffusion affected zones. Homogenization of Li and Cu alloyelements has been detected even in those cases where a metallic interlayer was used to favor the union.

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