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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
TL;DR: The C-MARS as mentioned in this paper is a cantilever microfabricated array of reference springs that can be used to calibrate an atomic force microscope (AFM) cantilevers using a binary code of surface oxide squares (easily visible in light, electron and atomic force microscopy).
Abstract: Calibration of atomic force microscope (AFM) cantilevers is necessary for the measurement of nanonewton and piconewton forces, which are critical to analytical applications of AFM in the analysis of polymer surfaces, biological structures and organic molecules. We have developed a compact and easy-to-use reference artefact for this calibration by bulk micromachining of silicon, which we call a cantilever microfabricated array of reference springs (C-MARS). Two separate reference cantilever structures, each nominally 3 µm thick, are fabricated from a single crystal silicon membrane. A binary code of surface oxide squares (easily visible in light, electron and atomic force microscopy) makes it easy to locate the position of the AFM tip along the length of the cantilevers. Uncertainty in location is the main source of error when calibrating an AFM using reference cantilevers, especially for those having spring constants greater than around 10 N m −1 . This error is effectively eliminated in our new design. The C-MARS device spans the range of spring constants from 25 N m −1 down to 0.03 N m −1 important in AFM, allowing almost any contact-mode AFM cantilever to be calibrated easily and rapidly.

75 citations

Journal ArticleDOI
01 Mar 1984-Vacuum
TL;DR: In this paper, the physical bases of Auger electron spectroscopy and X-ray photoelectron spectroscopic analysis are briefly presented in order that their practical applicability and limitations may be understood.

75 citations

Journal ArticleDOI
TL;DR: A method is described for comparing the sensitivity of two hydrophones over the frequency range 1-15 MHz, which forms the basis for the dissemination of national ultrasonic standards in the U.K. over this frequency range.
Abstract: A method is described for comparing the sensitivity of two hydrophones over the frequency range 1–15 MHz. This technique forms the basis for the dissemination of national ultrasonic standards in the U.K. over this frequency range. A reference hydrophone is placed in an ultrasonic field and then the device being calibrated is substituted and the two output voltages are compared. This substitution method utilizes a broadband ultrasonic field produced by nonlinear propagation. Thus it is possible to cover the whole frequency range with a single measurement on each hydrophone. The overall uncertainty in the intercomparison of two hydrophones increases from ±4.2% at 1 MHz to ±8.2% at 15 MHz (95% confidence level). The method has been compared with discrete‐frequency substitution, time‐delay spectrometry, and absolute calibrations using the National Physical Laboratory (NPL) primary standard laser interferometer. Various designs and sizes of hydrophones were compared, and agreement was within the combined random uncertainties for all the comparisons.

75 citations

Journal ArticleDOI
TL;DR: In this article, the authors explored electrochemically synthesized nanostructured NiCo 2 O 4 spinel thin-film electrode for electrochemical supercapacitors, which exhibited a high specific capacitance value of 580 F g − 1 and an energy density of 32 W − 1 at the power density of 4 W −1, accompanying with good cyclic stability.

75 citations

Journal ArticleDOI
TL;DR: The average life of a smoke particle before deposition on land is probably of the order of 1-2 days; that of a molecule of sulphur dioxide is estimated with rather more certainty to be less than 12 hours as mentioned in this paper.
Abstract: Observations of atmospheric pollution throughout Britain are considered in relation to the amounts of pollution emitted through the combustion of coal. The estimated weight of ash emitted into the air and the estimate, from deposit gauges, of the ash deposited, are considered likely to agree fairly well at a figure of rather over one million tons per annum (one million tonnes/yr). On the assumption that about 1.5 million tons of smoke are blown to sea each year, it is shown that about 1.1 million tons of sulphur dioxide are blown to sea each year; the remaining 0.8 million tons of smoke and 3.9 million tons of sulphur dioxide must be deposited in Britain, irrespective of the quantities measured in deposit gauges. The average life of a smoke particle before deposition on land is probably of the order of 1–2 days; that of a molecule of sulphur dioxide is estimated with rather more certainty to be less than 12 hours. Of the chlorides collected in deposit gauges more than half, as a rule, come from the sea, and less than half from the utilization of coal; but the ratio must vary with the position of the deposit gauge relative to the sea and to industries.

75 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