Endre søk
Begrens søket
1 - 7 of 7
Referera
Referensformat
• apa
• ieee
• modern-language-association-8th-edition
• vancouver
• Annet format
Fler format
Språk
• de-DE
• en-GB
• en-US
• fi-FI
• nn-NO
• nn-NB
• sv-SE
• Annet språk
Fler språk
Utmatningsformat
• html
• text
• asciidoc
• rtf
Treff pr side
• 5
• 10
• 20
• 50
• 100
• 250
Sortering
• Standard (Relevans)
• Forfatter A-Ø
• Forfatter Ø-A
• Tittel A-Ø
• Tittel Ø-A
• Type publikasjon A-Ø
• Type publikasjon Ø-A
• Eldste først
• Nyeste først
• Disputationsdatum (tidligste først)
• Disputationsdatum (siste først)
• Standard (Relevans)
• Forfatter A-Ø
• Forfatter Ø-A
• Tittel A-Ø
• Tittel Ø-A
• Type publikasjon A-Ø
• Type publikasjon Ø-A
• Eldste først
• Nyeste først
• Disputationsdatum (tidligste først)
• Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
• 1.
Diamond Light Source Ltd., Diamond House, Harwell Science Campus, Didcot, Oxfordshire, United Kingdom.
Departamento de Física Aplicada-Instituto de Ciencia de Materiales, Matter at High Pressure (MALTA) Consolider Team, Universidad de Valencia, Edificio de Investigación, Valencia, Spain. AWE, Aldermaston, Reading, United Kingdom. SUPA, School of Physics and Astronomy, and Centre for Science at Extreme Conditions,The University of Edinburgh, Edinburgh, United Kingdom. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Diamond Light Source Ltd., Diamond House, Harwell Science Campus, Didcot, Oxfordshire, United Kingdom. AWE, Aldermaston, Reading, United Kingdom. Departmento de Física, Universidad de La Laguna, Avda. Astrofísico Fco. Sánchez s/n, Tenerife, Spain. Institute of Earth Sciences Jaume Almera, CSIC, Barcelona, Spain. SUPA, School of Physics and Astronomy, and Centre for Science at Extreme Conditions,The University of Edinburgh, Edinburgh, United Kingdom. SUPA, School of Physics and Astronomy, and Centre for Science at Extreme Conditions,The University of Edinburgh, Edinburgh, United Kingdom. CELLS-ALBA Synchrotron Light Facility, Barcelona, Spain. DCITIMAC, MALTA Consolider Team, Universidad de Cantabria, Santander, Spain. AWE, Aldermaston, Reading, United Kingdom.
Phase diagram of calcium at high pressure and high temperature2018Inngår i: Physical review materials, ISSN 2475-9953, Vol. 2, nr 8, artikkel-id 083608Artikkel i tidsskrift (Fagfellevurdert)

Resistively heated diamond-anvil cells have been used together with synchrotron x-ray diffraction to investigate the phase diagram of calcium up to 50 GPa and 800 K. The phase boundaries between the Ca-I (fcc), Ca-II (bcc), and Ca-III (simple cubic, sc) phases have been determined at these pressure-temperature conditions, and the ambient temperature equation of state has been generated. The equation of state parameters at ambient temperature have been determined from the experimental compression curve of the observed phases by using third-order Birch-Murnaghan and Vinet equations. A thermal equation of state was also determined for Ca-I and Ca-II by combining the room-temperature Birch-Murnaghan equation of state with a Berman-type thermal expansion model.

• 2.
Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
Institut Jean Lamour, UMR 7198 CNRS–Université de Lorraine. LCPME UMR 7564 CNRS-Université de Lorraine. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Department of Physics Harvard University, Cambridge. Joint Institute for High Temperatures of RAS.
Single-Walled Carbon Nanotubes Shock-Compressed to 0.5 Mbar2017Inngår i: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 254, nr 11, artikkel-id 1700315Artikkel i tidsskrift (Fagfellevurdert)

Single-walled carbon nanotubes (SWCNTs) have been dynamically (shock) compressed to 0.5 Mbar, above the limit of their structural integrity. Two distinct types of material are identified by high-resolution transmission electron microscopy (HRTEM) and multi-wavelength Raman spectroscopy in the sample recovered after shock: multi-layer graphene (MLG) and a two-phase material composed of nano-clustered graphene and amorphous carbon whereas no diamond-like carbon or carbon nano-onions are found. Peak decomposition of the Raman spectra was used to estimate the coherent scatterers (clusters) size in MLG at 36 nm from the D- to G-band intensity ratio dependence on the photon excitation energy. Botella et al. (article no. 1700315) propose the peak fitting model for decomposition of the Raman spectra of highly disordered carbon material containing graphene nano-clusters and stress the importance of accounting for heptagonal- and pentagonal-ring defects in graphene layers for the analysis of such spectra. The cover image shows HRTEM images and the correspondent Raman spectra of the two types of material along with peak decomposition of the two-phase material with the peaks assigned to heptagons (a) and pentagons (b). Particulars of the SWCNTs transformation to other structural forms of carbon at high pressure/temperature are discussed

• 3.
Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
Institut Jean Lamour, UMR 7198 CNRS–Université de Lorraine. LCPME UMR 7564 CNRS-Université de Lorraine. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Department of Physics Harvard University, Cambridge. Joint Institute for High Temperatures of RAS.
Single-Walled Carbon Nanotubes Shock-Compressed to 0.5 Mbar2017Inngår i: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 254, nr 11, artikkel-id 1770259Artikkel i tidsskrift (Fagfellevurdert)

Single-walled carbon nanotubes (SWCNTs) have been dynamically (shock) compressed to 0.5 Mbar, above the limit of their structural integrity. Two distinct types of material are identified by high-resolution transmission electron microscopy (HRTEM) and multi-wavelength Raman spectroscopy in the sample recovered after shock: multi-layer graphene (MLG) and a two-phase material composed of nano-clustered graphene and amorphous carbon whereas no diamond-like carbon or carbon nano-onions are found. Peak decomposition of the Raman spectra was used to estimate the coherent scatterers (clusters) size in MLG at 36 nm from the D- to G-band intensity ratio dependence on the photon excitation energy. Botella et al. (article no. 1700315) propose the peak fitting model for decomposition of the Raman spectra of highly disordered carbon material containing graphene nano-clusters and stress the importance of accounting for heptagonal- and pentagonal-ring defects in graphene layers for the analysis of such spectra. The cover image shows HRTEM images and the correspondent Raman spectra of the two types of material along with peak decomposition of the two-phase material with the peaks assigned to heptagons (a) and pentagons (b). Particulars of the SWCNTs transformation to other structural forms of carbon at high pressure/temperature are discussed

• 4.
Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Department of Molecular Sciences and Nanosystems, Ca’ Foscari University of Venice, Venezia, Italy. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Departamento de Física, MALTA Consolider Team, Escuela Politécnica Superior, Universidad Carlos III de Madrid, Leganés, Spain. High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai, India. Process Development Division, Bhabha Atomic Research Centre, Mumbai, India. nstituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València, València, Spain. Departamento de Física Aplicada-ICMUV, Universidad de Valencia, MALTA Consolider Team, Edificio de Investigación, Burjassot, Spain. Departamento de Física Aplicada-ICMUV, Universidad de Valencia, MALTA Consolider Team, Edificio de Investigación, Burjassot, Spain.
Investigation on the Luminescence Properties of InMO(M = V5+, Nb5+, Ta5+) Crystals Doped with Tb3+ or Yb3+ Rare Earth Ions2020Inngår i: ACS omega, ISSN 2470-1343, Vol. 5, nr 5, s. 2148-2158Artikkel i tidsskrift (Fagfellevurdert)

We explore the potential of Tb- and Yb-doped InVO4, InTaO4, and InNbO4 for applications as phosphors for light-emitting sources. Doping below 0.2% barely change the crystal structure and Raman spectrum but provide optical excitation and emission properties in the visible and near-infrared (NIR) spectral regions. From optical measurements, the energy of the first/second direct band gaps was determined to be 3.7/4.1 eV in InVO4, 4.7/5.3 in InNbO4, and 5.6/6.1 eV in InTaO4. In the last two cases, these band gaps are larger than the fundamental band gap (being indirect gap materials), while for InVO4, a direct band gap semiconductor, the fundamental band gap is at 3.7 eV. As a consequence, this material shows a strong self-activated photoluminescence centered at 2.2 eV. The other two materials have a weak self-activated signal at 2.2 and 2.9 eV. We provide an explanation for the origin of these signals taking into account the analysis of the polyhedral coordination around the pentavalent cations (V, Nb, and Ta). Finally, the characteristic green (5D4 → 7FJ) and NIR (2F5/2 → 2F7/2) emissions of Tb3+ and Yb3+ have been analyzed and explained.

• 5.
Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
Universidad de Valencia, Valencia, Spain. Bhabha Atomic Research Centre, Mumbai, India. Homi Bhabha National Institute, Mumbai, India. Universidad de La Laguna, La Laguna, Spain. Departamento de Física, Instituto de Materiales y Nanotecnología, MALTA Consolider Team, Universidad de La Laguna, La Laguna, Spain. Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
High-pressure characterization of the optical and electronic properties of InVO4, InNbO4, and InTaO42019Inngår i: SN Applied Sciences, ISSN 2523-3963, Vol. 1, nr 5, artikkel-id 389Artikkel i tidsskrift (Fagfellevurdert)

We have studied the electronic properties at ambient pressure and under high pressure of InVO4, InNbO4, and InTaO4 powders, three candidate materials for hydrogen production by means of photocatalytic water splitting using solar energy. A combination of optical absorption and resistivity measurements and band structure calculations have allowed us to determine that these materials are wide band-gap semiconductors with a band-gap energy of 3.62(5), 3.63(5), and 3.79(5) eV for InVO4, InNbO4, and InTaO4, respectively. The last two compounds are indirect band-gap materials, and InVO4 is a direct band-gap material. The pressure dependence of the band-gap energy and the electrical resistivity have been determined too. In the three compounds, the band gap opens under compression until reaching a critical pressure, where a phase transition occurs. The structural transition triggers a band-gap collapse larger than 1.2 eV in the three materials, being the abrupt decrease in the band-gap energy related to an increase in the pentavalent cation coordination number. The phase transitions also cause changes in the electrical resistivity, which can be correlated with changes induced by pressure in the band structure. An explanation to the reported results is provided based upon ab initio calculations. The conclusions attained are of significance for technological applications of the studied oxides.

• 6.
School of Physics and Astronomy, The University of Edinburgh, Edinburgh, Edinburgh, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.
Diamond Light Source Ltd, Didcot, Oxfordshire, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND. Atomic Weapons Establishment, Aldermaston, West Berkshire, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND. Atomic Weapons Establishment, Aldermaston, West Berkshire, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND. School of Physics and Astronomy, The University of Edinburgh, Edinburgh, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND. Synchrotron Light Facility, ALBA, Cerdanyola del Valles, SPAIN. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Department of Applied Physics, Universidad de Valencia, Valencia, Burjassot, SPAIN. School of Physics and Astronomy, The University of Edinburgh, Edinburgh, Edinburgh, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.
The high-pressure, high-temperature phase diagram of cerium2020Inngår i: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648XArtikkel i tidsskrift (Fagfellevurdert)

We present an experimental study of the high-pressure, high-temperature behaviour of cerium up to $\sim$22 GPa and 820 K using angle-dispersive x-ray diffraction and external resistive heating. Studies above 820 K were prevented by chemical reactions between the samples and the diamond anvils of the pressure cells. We unambiguously measure the stability region of the orthorhombic \textit{oC}4 phase and find it reaches its apex at 7.1 GPa and 650 K. We locate the $\alpha$-\textit{cF}4 -- \textit{oC}4 -- \textit{tI}2 triple point at 6.1 GPa and 640 K, 1 GPa below the location of the apex of the \textit{oC}4 phase, and 1-2 GPa lower than previously reported. We find the $\alpha$-\textit{cF}4 $\rightarrow$ \textit{tI}2 phase boundary to have a positive gradient of 280 K/GPa, less steep than the 670 K/GPa reported previously, and find the \textit{oC}4 $\rightarrow$ \textit{tI}2 phase boundary to lie at higher temperatures than previously found. We also find variations as large as 2-3 GPa in the transition pressures at which the \textit{oC}4 $\rightarrow$ \textit{tI}2 transition takes place at a given temperature, the reasons for which remain unclear. Finally, we find no evidence that the $\alpha$-\textit{cF}4 $\rightarrow$ \textit{tI}2 is not second order at all temperatures up to 820 K.

• 7.
LSQM, Laboratory of Chemical Synthesis of Materials, Department of Materials Engineering, Federal University of Rio Grande do Norte, UFRN, Natal, RN, Brazil.
LSQM, Laboratory of Chemical Synthesis of Materials, Department of Materials Engineering, Federal University of Rio Grande do Norte, UFRN, Natal, RN, Brazil. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València, València, Spain. Departamento de Física Aplicada-ICMUV, Universidad de Valencia, MALTA Consolider Team, Edificio de Investigación, Burjassot, Spain. LSQM, Laboratory of Chemical Synthesis of Materials, Department of Materials Engineering, Federal University of Rio Grande do Norte, UFRN, Natal, RN, Brazil. LSQM, Laboratory of Chemical Synthesis of Materials, Department of Materials Engineering, Federal University of Rio Grande do Norte, UFRN, Natal, RN, Brazil. LSQM, Laboratory of Chemical Synthesis of Materials, Department of Materials Engineering, Federal University of Rio Grande do Norte, UFRN, Natal, RN, Brazil.
Spray pyrolysis synthesis and characterization of Mg1-xSrxMoO4 heterostructure with white light emission2020Inngår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 813, artikkel-id 152235Artikkel i tidsskrift (Fagfellevurdert)

Molybdates are inorganic materials with great potential in white phosphors application, being an alternative to traditional lighting sources. In this study, we report the synthesis and characterization of Mg1-xSrxMoO4 (x = 0, 0.25, 0.50, 0.75, and 1) powders with white light-emitting properties. Using X-ray diffraction, the formation of the monoclinic β-MgMoO4 phase was observed for x = 0 and the formation of the tetragonal scheelite phase of SrMoO4 was observed for x = 1. The formation of a heterostructure composed of both phases was found for compositions with x = 0.25, 0.50 and 0.75. Scanning electron microscopy images showed that the Mg1-xSrxMoO4 particles exhibit a spherical morphology formed by several primary nanoparticles. Raman scattering spectroscopy enabled the accurate identification of the Raman modes for different compositions and their assignment to either the SrMoO4 or β-MgMoO4 modes. The bandgap energies were determined to fluctuate between 4.25 eV and 4.44 eV, being influenced by the degree of structural disorder. The photoluminescence emission spectra of the nanoparticles showed neutral- and cool-white emission with high-quality white light (CRI > 80%). The samples synthesized with x ≤ 0.50 are potential materials for the application in LED lamps (6500 K) and pure white-light sources (5500 K).

1 - 7 of 7
Referera
Referensformat
• apa
• ieee
• modern-language-association-8th-edition
• vancouver
• Annet format
Fler format
Språk
• de-DE
• en-GB
• en-US
• fi-FI
• nn-NO
• nn-NB
• sv-SE
• Annet språk
Fler språk
Utmatningsformat
• html
• text
• asciidoc
• rtf