Institution
National Physical Laboratory
Facility•London, 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 published on a yearly basis
Papers
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TL;DR: Level crossing in the optical whispering-gallery (WG) modes is studied by using toroidal microcavities to calculate crossings of levels that correspond with the observed degenerate modes, where the method takes into account the not perfectly transverse nature of their field polarizations.
Abstract: We study level crossing in the optical whispering-gallery (WG) modes by using toroidal microcavities. Experimentally, we image the stationary envelope patterns of the composite optical modes that arise when WG modes of different wavelengths coincide in frequency. Numerically, we calculate crossings of levels that correspond with the observed degenerate modes, where our method takes into account the not perfectly transverse nature of their field polarizations. In addition, we analyze anticrossing with a large avoidance gap between modes of the same azimuthal number.
87 citations
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TL;DR: In this article, the authors examined the nature and magnitude of the decrease as a function of flare flux, developed model recombination coefficient profiles for different flare conditions, and then offer a theory of how these decreases can occur.
87 citations
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TL;DR: In this article, the crystal structure, surface morphology, dielectric and electrical properties of tungsten doped SrBi 2 (W x Ta 1− x ) 2 O 9 (0.20) ferroelectric ceramics were investigated.
Abstract: In this study, investigations have been made on the crystal structure, surface morphology, dielectric and electrical properties of tungsten doped SrBi 2 (W x Ta 1− x ) 2 O 9 (0.0 ≤ x ≤ 0.20) ferroelectric ceramics. Dielectric measurements performed as a function of temperature at 1, 10 and 100 kHz show an increase in Curie temperature ( T c ) over the composition range of x = 0.05–0.20. W 6+ substitution in perovskite-like units results in a sharp dielectric transition at the ferroelectric Curie temperature with the dielectric constant at their respective Curie temperature increasing with tungsten doping. The dielectric loss reduces significantly with tungsten addition. The temperature dependence of ac and dc conductivity vis-a-vis tungsten content shows a decrease in conductivity, which is attributed to the suppression of oxygen vacancies. The activation energy calculated from the Arrhenius plots is found to increase with tungsten content.
87 citations
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TL;DR: In this paper, Aluminide coatings on ferritic-martensitic steels produced by applying an Al slurry followed by a diffusion heat treatment, have shown to be protective at 650 °C under steam for at least 32,000 h of laboratory steam exposure under atmospheric pressure.
Abstract: Important efforts to develop new steels or to protect high creep strength steels in order to allow operation of steam turbines at 650 °C are being carried out world-wide to increase efficiency. Within the European Project “SUPERCOAT” (Coatings for Supercritical Steam Cycles), work has been concentrated in the development of coatings to withstand 50,000–100,000 h of operation at 650 °C under high pressure steam. Aluminide coatings on ferritic–martensitic steels produced by applying an Al slurry followed by a diffusion heat treatment, have shown to be protective at 650 °C under steam for at least 32,000 h of laboratory steam exposure under atmospheric pressure. Although the “as diffused” coatings present through thickness cracks, these do not propagate during exposure to steam or thermal cycling and no new cracks seem to develop. Moreover, no changes in residual stresses could be observed after thermal cycling. Microstructural characterization of samples at different periods of exposures has been carried out by SEM-EDS and XRD. The principal mechanism of coating degradation is loss of Al at the surface due to inwards diffusion. Microhardness as well as Young's modulus and fracture strength were measured using well established techniques. The coatings show reasonable ductility (∼1.6%) when stressed in tension between room temperature and 400 °C which further increases at higher temperatures providing evidence that the coatings should withstand the mechanical conditions likely to be encountered in service.
86 citations
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TL;DR: In this paper, a 3 NiCrMoV steam turbine disc steel in the form of cylindrical tensile test specimens self-loaded to 90% of σ 0.2 and exposed to three environmental conditions, viz. deaerated pure water, aerated pure waters, and aerated water containing 1.5 ppm of chloride ion.
86 citations
Authors
Showing all 7655 results
Name | H-index | Papers | Citations |
---|---|---|---|
Rajesh Kumar | 149 | 4439 | 140830 |
Akhilesh Pandey | 100 | 529 | 53741 |
A. S. Bell | 90 | 305 | 61177 |
David R. Clarke | 90 | 553 | 36039 |
Praveen Kumar | 88 | 1339 | 35718 |
Richard C. Thompson | 87 | 380 | 45702 |
Xin-She Yang | 85 | 444 | 61136 |
Andrew J. Pollard | 79 | 673 | 26295 |
Krishnendu Chakrabarty | 79 | 996 | 27583 |
Vinod Kumar | 77 | 815 | 26882 |
Bansi D. Malhotra | 75 | 375 | 19419 |
Matthew Hall | 75 | 827 | 24352 |
Sanjay K. Srivastava | 73 | 366 | 15587 |
Michael Jones | 72 | 331 | 18889 |
Sanjay Singh | 71 | 1133 | 22099 |