| 1. |
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| 2. |
- Alm, Ove, et al.
(författare)
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Thermal conductivity of KCl up to 19 kbar
- 1974
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Ingår i: Journal of Physics and Chemistry of Solids. - : Elsevier. - 0022-3697 .- 1879-2553. ; 35:3, s. 421-424
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Tidskriftsartikel (refereegranskat)abstract
- The pressure dependency of the thermal conductivity of KCl has been measured at room temperature up to 19 kbar. The high pressure tool was of the “belt” type and a solid medium was used. The specimen was cylindrical and was heated along its axis. The conductivity was found to increase linearly at a rate of (3·3 ± 0·3) per cent/kbar.
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| 3. |
- Andersson, Ove, et al.
(författare)
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Thermal conductivity of normal and deuterated tetrahydrofuran clathrate hydrates
- 1996
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Ingår i: Journal of Physics and Chemistry of Solids. - : Elsevier. - 0022-3697 .- 1879-2553. ; 57:1, s. 125-132
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Tidskriftsartikel (refereegranskat)abstract
- The thermal conductivity λ of normal and deuterated tetrahydrofuran (THF) clathrate hydrates has been measured at temperatures in the range 55-250 K and at pressures up to 0.16 GPa. The normal and deuterated samples exhibited the same values of λ to within 5%. At isobaric heating, the transition from the proton ordered low temperature (LT) phase to the proton disordered high temperature (HT) phase was detected as a discontinuous decrease of λ by about 15% for both the normal and the deuterated samples. The magnitude is nearly the same as that found previously for the related transition phase XI → phase Ih of ice and might be due to a change in the lattice anharmonicity. The thermal conductivity of the LT and HT phases increased slightly with increasing temperature and, hence, these crystalline phases exhibited both a glass-like λ(T). These results can be described using the resonance scattering model in which the phonons are scattered against THF vibrations. The LT phase of both samples exhibited a slight increase of λ with increasing pressure whereas that of the HT phases was roughly independent of pressure, showing that λ does not depend on density.
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| 4. |
- Andersson, Per
(författare)
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Thermal conductivity and heat capacity of cyclohexane under pressure
- 1978
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Ingår i: Journal of Physics and Chemistry of Solids. - : Elsevier. - 0022-3697 .- 1879-2553. ; 39:1, s. 65-68
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Tidskriftsartikel (refereegranskat)abstract
- The transient hot-wire technique was used to determine the thermal conductivity, λ, and the specific heat capacity per unit volume, ρcp, of cyclohexane up to 1.5 GPa in the range 120–340 K. The measurements were carried out in a piston-cylinder apparatus, 45 mm in internal diameter, cooled by liquid nitrogen. There is only a small (6%) increase in λ on freezing, while there is an increase by a factor of two corresponding to the plastic→ normal crystal transition. The variation of λ with temperature (T) at P = 0.03 GPa is d(lnλ)/dT = −2.2×10−3K−1 for the liquid and d(ln λ)/dT = −0.9×10−3K−1 for the plastic crystalline phase. In the normal crystal phase an approximate T−1 dependence is observed. Within each of the phases λ increases linearly with pressure, and the slope of λ (P) is smallest in the plastic crystal phase. The existence of a recently reported new high pressure phase is evident from conductivity data. Qualitative ρcp -results are reported.
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| 5. |
- Buga, Sergei G., et al.
(författare)
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DSC study of annealing and phase transformations of C60 and C70 polymerized under pressures in the range 9.5 - 13 GPa.
- 2002
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Ingår i: Journal of Physics and Chemistry of Solids. - : Elsevier B.V.. - 0022-3697 .- 1879-2553. ; 63:2, s. 331-343
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Tidskriftsartikel (refereegranskat)abstract
- C60 and C70 fullerenes polymerized under pressures between 9.5 and 13 GPa and temperatures between 670 and 1850 K were investigated by differential scanning calorimetry (DSC) in the range 240–640 K. Endothermal heat effects were observed with a peak maximum just below 540 K, a temperature characteristic for breakdown of (2+2) intermolecular links in dimers, 1D and 2D polymers. Exothermal effects, starting from 380 K, were observed for the first time in polymeric fullerenes. These effects are attributed to relaxation processes and to breakdown of other types of intermolecular bonds such as common four-sided rings and (3+3) interlinks.
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| 6. |
- Edman, Ludvig, et al.
(författare)
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Sodium-sodium halide co-intercalated graphite: chemistry, structure and electrical transport
- 1999
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Ingår i: Journal of Physics and Chemistry of Solids. - : Elsevier B.V.. - 0022-3697 .- 1879-2553. ; 60:4, s. 475-482
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Tidskriftsartikel (refereegranskat)abstract
- This study deals with the second to fourth stage compounds resulting from the co-intercalation of sodium and sodium halides into graphite. The charge transfer was determined through chemical analyses and X-ray diffraction and the results are compatible with Raman spectroscopy data. We present detailed results on c axis conduction between 4.2 K and 295 K and for hydrostatic pressures as high as 1.6 GPa. Possible mechanisms explaining the c axis conduction are discussed.
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| 7. |
- Håkansson, Björn, et al.
(författare)
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Thermal conductivity and heat capacity of solid NaCl and NaI under pressure
- 1986
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Ingår i: Journal of Physics and Chemistry of Solids. - : Elsevier. - 0022-3697 .- 1879-2553. ; 47:4, s. 355-362
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Tidskriftsartikel (refereegranskat)abstract
- We measured the thermal conductivity and heat capacity per unit volume for solid NaCl and NaI using the transient hot-wire technique. Measurements were performed in the temperature range 100–400 K and at pressures up to 2 GPa. Analysis of the thermal conductivity data showed that the Leibfried-Schlömann formula is a better description for NaCl than for NaI. For both NaCl and NaI the effect of optic phonons on thermal conductivity cannot be ignored. However, taking only acoustic phonons into account is a better approximation for NaI than for NaCl, due to the larger ionic mass ratio for NaI. The specific heat capacities, obtained at room temperature, were approximately independent of pressure.
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| 8. |
- Jacobsson, Per, et al.
(författare)
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Pressure dependence of the thermal and electrical conductivities of the intermetallic compounds AuCu and AuCu3
- 1988
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Ingår i: Journal of Physics and Chemistry of Solids. - : Elsevier BV. - 0022-3697 .- 1879-2553. ; 49:4, s. 441-450
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Tidskriftsartikel (refereegranskat)abstract
- The thermal diffusivity, a, electrical resistivity, ρ, and Seebeck coefficient, S, of ordered and disordered AuCu3 and AuCu have been measured as functions of T and P in the range 100–300 K and 0–2 GPa, and the thermal conductivity, λ, has been calculated from the data for a. The experimental data for ρ agree well with literature data. The ρ dependence of ρ and λ differs significantly between ordered and disordered specimens, but apart from the effect of impurity scattering the disordered materials behave much like the noble metals. For the temperature-dependent part of p (and λ) the P dependence differs by a factor of 2–3 between ordered and disordered states. This is shown to result from the difference in electron band structure, as reflected also in the thermoelectric parameter ξ. The P dependence of the relatively large lattice thermal conductivity of these materials causes the Lorenz ratio L = λρ/T to increase with ρ in all cases.
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| 9. |
- Jansson, Roger, et al.
(författare)
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Optical and microstructural characterization of thin films of photochromic fulgides
- 2001
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Ingår i: Journal of Physics and Chemistry of Solids. - 0022-3697 .- 1879-2553. ; 62:7, s. 1219-1228
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Tidskriftsartikel (refereegranskat)abstract
- Variable angle spectroscopic ellipsometry has been used for determining the optical properties, in terms of the complex dielectric function in the near UV-VIS-near IR spectral range, and the thicknesses of thin fulgide films of type E-a-(2,5-dimethyl-3-furyl)-ethylidene(adamantylidene)succinic anhydride and (E)-2-[a-(2,5-dimethyl-3-thienyl)ethylidene]-3-isopropylidenesuccinic anhydride. The films had thicknesses in the range 28-40 nm and were spin coated onto silicon substrates. To simultaneously extract film thicknesses and optical properties of the films, several methods of analysis were employed in order to decrease correlation between the fitting parameters in the optical model of the structure. In agreement with previous absorbance measurements done by others on similar materials in liquid or solid form, it was found that the fulgides studied have several resonances in the wavelength region below 400 nm and that new resonances appear in the middle of the visible region upon UV exposure. The ellipsometric analysis, as well as atomic force microscopy studies, showed that the films were very smooth with a root mean square surface roughness <0.4 nm and that a small thickness change of the film takes place upon UV exposure. Furthermore, AFM studies revealed that large phase changes take place when the samples are stored in darkness for several days, indicating that the materials are not stable in thin film form. © 2001 Elsevier Science Ltd.
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| 10. |
- Persson, Per-Axel, et al.
(författare)
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The physical properties of high-pressure polymerized C60
- 1997
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Ingår i: Journal of Physics and Chemistry of Solids, volume 58, issue 11. - : Elsevier B.V.. ; 58:11, s. 1881-1885
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Konferensbidrag (refereegranskat)abstract
- We have studied the structural, thermophysical, and spectroscopic properties of polymeric C60 obtained by high pressure treatment at pressures and temperatures near 1 GPa and 600 K. We present here a brief overview of our results for the structural and thermophysical properties and a more detailed report on recent results obtained by Raman spectroscopy on both thin films, polycrystalline, and single crystal material. The results presented include a comparison between Raman results for photopolymerized and pressure polymerized thin films and a preliminary estimate of the binding energy of polymeric C60.
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