Search query: A nanometre-scale mechanical electrometer

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abstract: The mechanical detection of charge has a long history, dating back more than 200 years to Coulomb's torsion balance electrometer. The modern analogues of such instruments are semiconductor based field effect devices, the most sensitive of which are cryogenically cooled single electron transistors. But although these latter devices have extremely high charge sensitivity, they suffer from limited bandwidth and must be operated at millikelvin temperatures in order to reduce thermal noise. Here we report the fabrication and characterization of a working nanometre scale mechanical electrometer. We achieve a charge sensitivity of 0.1 e Hz 0.5, competitive with conventional semiconductor field effect transistors; moreover, thermal noise analysis indicates that the nanometre scale electrometer should ultimately reach sensitivities of the order of 10 6 e Hz 0.5, comparable with charge detection capabilities of cryogenic single electron transistors. The nanometre scale electrometer has the additional advantages of high temperature (4.2 K) operation and response over a larger bandwidth, from which a diversity of applications may result.
author_names: Andrew N Cleland

Michael L Roukes
title: A nanometre scale mechanical electrometer
venue: Nature
year: 1998

abstract: This paper characterises the pore types and their distribution in the Vaca Muerta Formation, Neuquen Basin, Argentina. This formation is now being studied and targeted as reservoir rock, and it is therefore considered an unconventional resource play. There is significant need for a porosity description as part of the unconventional reservoir characterisation. Mineral compositions, grain assemblages, morphology, organic content and distribution, and micron to nanometre scale pore types are studied through scanning electron microscopy. Petrographic observations depict the complex response of pores to chemical and mechanical processes, where both destruction of primary porosity and generation of secondary pores are common. Compaction, cementation and infill of migrated organic matter destroy primary porosity whereas dissolution and secondary organic matter generated through maturation create secondary pores. Lamina sets with major detrital components can help identify intervals with higher interparticle and intraparticle porosity. Interparticle and intraparticle porosity are ubiquitous throughout the samples. Interparticle pores are common around rigid detrital grains, like quartz and feldspar, and within detrital clay platelets. Porosity within authigenic clay cements is included, as framework porosity and samples may contain up to a maximum of 30 wt% clay. Partial grain dissolution of coccoliths, feldspars and calcite grains resulted in available intraparticle pore space. Organopores are the least abundant pore types at this location. Organopores were described within migrated organic matter. Although the kerogen type (Type II) and the vitrinite reflectance are optimum for hydrocarbon generation (ca 0.80% Ro) in the Vaca Muerta Formation at the study area, development of organopores is not common. The Vaca Muerta Formation has experienced insufficient thermal maturation (early oil window) and has not yet reached peak oil.
author_names: Eider Hernandez-Bilbao

J Rick Sarg

Stephen A Sonnenberg
title: Micron to nanometre scale pore characterisation of the early oil window Vaca Muerta Formation, Neuquen Basin, Argentina
year: 2020

abstract: To devise new strategies to treat bone disease in an ageing society, a more detailed characterisation of the process by which bone mineralises is needed. In vitro studies have suggested that carbonated mineral might be a precursor for deposition of bone apatite. Increased carbonate content in bone may also have significant implications in altering the mechanical properties, for example in diseased bone. However, information about the chemistry and coordination environment of bone mineral, and their spatial distribution within healthy and diseased tissues, is lacking. Spatially resolved analytical transmission electron microscopy is the only method available to probe this information at the length scale of the collagen fibrils in bone. In this study, scanning transmission electron microscopy combined with electron energy loss spectroscopy (STEM EELS) was used to differentiate between calcium containing biominerals (hydroxyapatite, carbonated hydroxyapatite, beta tricalcium phosphate and calcite) A carbon K edge peak at 290 eV is a direct marker of the presence of carbonate. We found that the oxygen K edge structure changed most significantly between minerals allowing discrimination between calcium phosphates and calcium carbonates. The presence of carbonate in carbonated HA (CHA) was confirmed by the formation of peak at 533 eV in the oxygen K edge. These observations were confirmed by simulations using density functional theory. Finally, we show that this method can be utilised to map carbonate from the crystallites in bone. We propose that our calibration library of EELS spectra could be extended to provide spatially resolved information about the coordination environment within bioceramic implants to stimulate the development of structural biomaterials.
author_names: Michal M Klosowski

Robert J Friederichs

Robert Nichol

Nikolas Antolin

Raffaella Carzaniga

Wolfgang Windl

Serena M Best

Sandra J Shefelbine

David W McComb

Alexandra E Porter
title: Probing carbonate in bone forming minerals on the nanometre scale.
venue: Acta biomaterialia
year: 2015

abstract: Future 'smart' structures have the potential to revolutionize many engineering applications. One of the possible methods for creating smart structures is through the use of shape memory alloy (SMA) fibres embedded into metal matrices. Ultrasonic consolidation (UC) allows the embedding of SMAs into metal matrices while retaining the SMA's intrinsic recoverable deformation property. In this work, NiTi SMA fibres were successfully embedded into an Al 3003 (0) matrix via the UC layer manufacturing process. Initially the plastic flow of the Al matrix and the degree of fibre encapsulation were observed using optical microscopy. Then microstructural grain and sub grain size variation of the Al 3003 (0) matrix at the fibre matrix interface, and the nature of the fibre matrix bonding mechanism, were studied via the use of focused ion beam (FIB) cross sectioning, FIB imaging, scanning electron microscopy, and mechanical peel testing. The results show that the inclusion of the NiTi SMA fibres had a significant effect on the surrounding Al matrix microstructure during the UC process. Additionally, the fibre matrix bonding mechanism appeared to be mechanical entrapment with the SMA surface showing signs of fatigue from the UC embedding process.
author_names: Ross J Friel

Russell A Harris
title: A nanometre scale fibre to matrix interface characterization of an ultrasonically consolidated metal matrix composite
year: 2010

abstract: This paper introduces a new experimental method to monitor the evolving intra particle, nanometre scale response during hydro mechanical tests on undisturbed wet clay samples using small angle X ray scattering (SAXS) The method uses a newly developed miniature plane strain one dimensional compression cell that facilitates simultaneous full field surface displacement measurements using digital image correlation and SAXS measurements. The 60 120 s acquisition times offered by SAXS at synchrotron facilities are beneficial to study time dependent mechanisms in clays. The experimental results presented indicate that, for the natural sensitive clay tested in this work, no significant structural changes occur at the intra particle scale during loading, even when large strains are measured at the macro scale. In addition, changes that are observed at this scale occur after the end of perturbation, i.e. the creation of new intra particle structures. Further information is obtained on the orientation evolution of the fabric by the comparative analysis of the individual mineral component response.
author_names: Georgios Birmpilis

Stephen A Hall

Sebastian Lages

Jelke Dijkstra
title: Monitoring of the nano structure response of natural clay under mechanical perturbation using small angle X ray scattering and digital image correlation
venue: Acta Geotechnica
year: 2019

abstract: In the last decade, considerable research effort was directed to the deposition of multilayer films with layer thicknesses in the nanometer range (superlattice coatings) in order to increase the performance of various cutting tools and machine parts. The goal of the present work was to investigate the main microstructural, mechanical and wear resistance characteristics of a superlattice coating, consisting of alternate multilayer ZrN/TiAIN films, with various bilayer periods (5 20 nm) The coatings were deposited by the cathodic arc method on Si, plain carbon steel and high speed steel substrates to be used as wear resistance surfaces. The multilayer structures were prepared by using shutters placed in front of each cathode (Zr and Ti+Al) The characteristics of multilayer structures (elemental and phase composition, texture, Vickers microhardness, thickness, adhesion, and wear resistance) were determined by using various techniques (AES, XPS, XRD, microhardness measurements, scratch, and tribological tests) A comparison with the properties of ZrN and TiAIN single layer coatings was carried out.
author_names: Alina Vladescu

Attila Kiss

Aurelian A Popescu

Mariana Braic

Mihai Balaceanu

Viorel Braic

Ioan Albert Tudor

Constantin Logofatu

Constantin Catalin Negrila

R G Rapeanu
title: Influence of bilayer period on the characteristics of nanometre scale ZrN/TiAIN multilayers.
venue: Journal of nanoscience and nanotechnology
year: 2008

abstract: The widely used 'silicon on insulator' (SOI) system consists of a layer of single crystalline silicon supported on a silicon dioxide substrate. When this silicon layer (the template layer) is very thin, the assumption that an effectively infinite number of atoms contributes to its physical properties no longer applies, and new electronic, mechanical and thermodynamic phenomena arise, distinct from those of bulk silicon. The development of unusual electronic properties with decreasing layer thickness is particularly important for silicon microelectronic devices, in which (001) oriented SOI is often used. Here we show using scanning tunnelling microscopy, electronic transport measurements, and theory that electronic conduction in thin SOI(001) is determined not by bulk dopants but by the interaction of surface or interface electronic energy levels with the 'bulk' band structure of the thin silicon template layer. This interaction enables high mobility carrier conduction in nanometre scale SOI; conduction in even the thinnest membranes or layers of Si(001) is therefore possible, independent of any considerations of bulk doping, provided that the proper surface or interface states are available to enable the thermal excitation of 'bulk' carriers in the silicon layer.
author_names: Pengpeng Zhang

Emma Tevaarwerk

Byoung-Nam Park

Donald E Savage

George K Celler

Irena Knezevic

Paul G Evans

Mark A Eriksson

Max G Lagally
title: Electronic transport in nanometre scale silicon on insulator membranes
venue: Nature
year: 2006

abstract: The lipid bilayer component of biological membranes is a two dimensional liquid under physiological conditions. Computer simulation calculations based on statistical mechanical models predict this liquid to exhibit structure in the form of fluctuating lipid domains in the nanometre range. Indirect and direct experimental evidence for the small scale structure is provided by fluorescence energy transfer techniques and atomic force microscopy, respectively.
author_names: Lars K Nielsen

A N Vishnyakov

Kent Jorgensen

Thomas Bjornholm

Ole G Mouritsen
title: Nanometre scale structure of fluid lipid membranes
year: 2000

abstract: Local oxidation of silicon surfaces by scanning probe microscopy is a very promising lithographic approach at nanometre scale. Here, we present two approaches to optimize the oxidation for nanofabrication purposes: (i) we analyse the reproducibility and kinetics of the oxidation of Si(100) surfaces when there is no tip and sample mechanical contact and (ii) we study the effect of modulating the voltage in the aspect ratio of the oxide structures grown. The finite tip sample separation has remarkable practical consequences: the same tip can be used to perform thousands of modifications without any sign of wear. In addition, the structures generated do not show any degradation over long periods (months) It is also found that the kinetics is independent of the force microscopy mode used (contact or non contact) On the other hand, the application of an AC voltage to induce the oxidation significantly modifies the aspect ratio of the structures. A detailed description of the oxidation mechanism is proposed to account for both results.
author_names: Montserrat Calleja

Jose V Anguita

Ricardo Garcia

Karen Birkelund

Francesc Perez-Murano

John A Dagata
title: Nanometre scale Oxidation of Silicon Surfaces by Dynamic Force Microscopy: Reproducibility, Kinetics and Nanofabrication
year: 1999

abstract: Understanding the relative motion of objects in contact is essential for controlling macroscopic lubrication and adhesion, for comprehending biological macromolecular interfaces, and for developing submicrometre scale electromechanical devices, An object undergoing lateral motion while in contact with a second object can either roll or slide. The resulting energy loss and mechanical wear depend largely on which mode of motion occurs. At the macroscopic scale, rolling is preferred over sliding, and it is expected to have an equally important role in the microscopic domain. Although progress has been made in our understanding of the dynamics of sliding at the atomic level, we have no comparable insight into rolling owing to a lack of experimental data on microscopic length scales. Here we produce controlled rolling of carbon nanotubes on graphite surfaces using an atomic force microscope. We measure the accompanying energy loss and compare this with sliding. Moreover, by reproducibly rolling a nanotube to expose different faces to the substrate and to an external probe, we are able to study the object over its complete surface.
author_names: Michael R Falvo

R M Taylor

Aron T Helser

V Chi

Frederick P Brooks

Sean Washburn

Richard Superfine
title: Nanometre scale rolling and sliding of carbon nanotubes
venue: Nature
year: 1999