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Institution

National Physical Laboratory

FacilityLondon, United Kingdom
About: National Physical Laboratory is a facility organization based out in London, United Kingdom. It is known for research contribution in the topics: Dielectric & Thin film. The organization has 7615 authors who have published 13327 publications receiving 319381 citations.


Papers
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Journal ArticleDOI
11 Jul 2012-Langmuir
TL;DR: A comparative study of emerging and established techniques to size submicrometer and nanometer sized particles, evaluating their sizing precision and relative resolution, and demonstrating the variety of physical principles upon which they are based is presented.
Abstract: The accurate characterization of submicrometer and nanometer sized particles presents a major challenge in the diverse applications envisaged for them including cosmetics, biosensors, renewable energy, and electronics. Size is one of the principal parameters for classifying particles and understanding their behavior, with other particle characteristics usually only quantifiable when size is accounted for. We present a comparative study of emerging and established techniques to size submicrometer particles, evaluating their sizing precision and relative resolution, and demonstrating the variety of physical principles upon which they are based, with the aim of developing a framework in which they can be compared. We used in-house synthesized Stober silica particles between 100 and 400 nm in diameter as reference materials for this study. The emerging techniques of scanning ion occlusion sensing (SIOS), differential centrifugal sedimentation (DCS), and nanoparticle tracking analysis (NTA) were compared to the established techniques of transmission electron microscopy (TEM), scanning mobility particle sizing (SMPS), and dynamic light scattering (DLS). The size distributions were described using the mode, arithmetic mean, and standard deviation. Uncertainties associated with the six techniques were evaluated, including the statistical uncertainties in the mean sizes measured by the single-particle counting techniques. Q-Q plots were used to analyze the shapes of the size distributions. Through the use of complementary techniques for particle sizing, a more complete characterization of the particles was achieved, with additional information on their density and porosity attained.

150 citations

Journal ArticleDOI
TL;DR: The electrochemical sensing results of the anti-AFB1/RGO/ITO based immunoelectrode obtained as a function of aflatoxin concentration show high sensitivity and improved detection limit and the association constant for antigen-antibody interaction obtained as 5 × 10(-4) ng mL(-1) indicates high affinity of antibodies toward the antigen ( AFB1).
Abstract: Reduced graphene oxide (RGO) due to its excellent electrochemical properties and large surface area, has recently aroused much interest for electrochemical biosensing application. Here, the chemically active RGO has been synthesized and deposited onto an indium tin oxide (ITO) coated glass substrate by the electrophoretic deposition technique. This novel platform has been utilized for covalent attachment of the monoclonal antibodies of aflatoxin B1 (anti-AFB1) for food toxin (AFB1) detection. The electron microscopy, X-ray diffraction, and UV-visible studies reveal successful synthesis of reduced graphene oxide while the XPS and FTIR studies suggest its carboxylic functionalized nature. The electrochemical sensing results of the anti-AFB1/RGO/ITO based immunoelectrode obtained as a function of aflatoxin concentration show high sensitivity (68 μA ng−1 mL cm−2) and improved detection limit (0.12 ng mL−1). The association constant (ka) for antigen–antibody interaction obtained as 5 × 10−4 ng mL−1 indicates high affinity of antibodies toward the antigen (AFB1).

150 citations

Journal ArticleDOI
TL;DR: In this paper, the lattice stabilities for the metastable FCC (Al), BCC (A2) and CPH (A3) allotropes of 43 elements have been evaluated.
Abstract: Lattice stabilities for the metastable FCC (Al), BCC (A2) and CPH (A3) allotropes of 43 elements have been evaluated. The results are based on (1) Assessed stable phase data; (2) Phase boundary extrapolations from binary alloy, and elemental pressure-temperature, phase diagrams; (3) A relationship between the entropy of fusion, crystal structure and melting point; (4) Stacking fault energies; (5) Periodic and group trends and (6) First principle electronic energy calculations. Qualitative trends proposed by previous thermochemical evaluations for the transition metals are to a large extent confirmed. However, the evaluated energy differences between the different crystal allotropes are substantially higher and can be closer in magnitude to those predicted by ab-initio electron energy calculations, although particular discrepancies, for example concerning Cr(FCC), still remain. Many of the changes proposed here arise from the reassessment of stable phase data, particularly with respect to recently measured heats of fusion of the high melting point elements.

150 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used a scanning force microscope (SFM) scanner with three laser interferometers fitted in the co-ordinate axes x, y and z to measure the area function near the indenter tip.

150 citations

Journal ArticleDOI
TL;DR: The calculation of the electron spatial distribution in the confinement potential shows that the high-mobility electrons responsible for superconductivity set at the edge of the gas whose extension can be tuned by the field effect.
Abstract: In this Letter, we show that a superconducting two-dimensional electron gas is formed at the LaTiO3/SrTiO3 interface whose transition temperature can be modulated by a back-gate voltage. The gas consists of two types of carriers: a majority of low-mobility carriers always present, and a few high-mobility ones that can be injected by electrostatic doping. The calculation of the electron spatial distribution in the confinement potential shows that the high-mobility electrons responsible for superconductivity set at the edge of the gas whose extension can be tuned by the field effect.

149 citations


Authors

Showing all 7655 results

NameH-indexPapersCitations
Rajesh Kumar1494439140830
Akhilesh Pandey10052953741
A. S. Bell9030561177
David R. Clarke9055336039
Praveen Kumar88133935718
Richard C. Thompson8738045702
Xin-She Yang8544461136
Andrew J. Pollard7967326295
Krishnendu Chakrabarty7999627583
Vinod Kumar7781526882
Bansi D. Malhotra7537519419
Matthew Hall7582724352
Sanjay K. Srivastava7336615587
Michael Jones7233118889
Sanjay Singh71113322099
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202315
202242
2021356
2020438
2019434
2018406