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- Johansson, M P, et al.
(author)
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Low-temperature deposition of cubic BN : C films by unbalanced direct current magnetron sputtering of a B4C target
- 1996
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In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : American Institute of Physics (AIP). - 0734-2101 .- 1520-8559. ; 14:6, s. 3100-3107
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Journal article (peer-reviewed)abstract
- Controllable-unbalanced de magnetron sputtering of a B4C target in mixed Ar-N-2 discharges has been used to deposit BN:C thin films with carbon concentrations in the range of 5-21 at, % on Si(001) substrates. The variation of the nitrogen gas consumption with nitrogen partial pressure was used to determine the sorption capacity of the sputtering source and was then correlated to the film discharge plasma density near the substrate in a wide range. Hence, the ion flux J(i) of primary Ar+ and N-2(+) ions accelerated to the substrate by an applied negative substrate bias could be varied while keeping the deposition flux J(n) (the sum of film building species, B, C, and N atoms) near constant. BN:C films were grown at large ion-to-neutral flux ratios 3 less than or equal to J(i)/J(n) less than or equal to 24, ion energies E(i) less than or equal to 500 eV, and substrate temperatures 150 less than or equal to T-s less than or equal to 350 degrees C. The phase and elemental composition of as-deposited BN:C films were characterized by Fourier transform infrared spectroscopy and wavelength dispersive x-ray spectroscopy, respectively. Deposition of cubic phase c-BN:C containing 5-7 at. % of C is demonstrated under conditions of low energy (110 eV) ion bombardment, a high ion-to-atom arrival rate ration (J(i)/J(n) similar to 24), and low growth temperatures (similar to 150 degrees C). (C) 1996 American Vacuum Society.
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| 2. |
- Jonsdottir, Ingibjörg H, 1966, et al.
(author)
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Increase in nitric oxide formation after chronic voluntary exercise in spontaneously hypertensive rats.
- 1998
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In: Acta physiologica Scandinavica. - 0001-6772. ; 162:2, s. 149-53
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Journal article (peer-reviewed)abstract
- The effect of chronic voluntary exercise on the plasma level of nitrate, a major stable metabolite of nitric oxide (NO) was studied in spontaneously hypertensive rats (SHR). Exercise consisted of spontaneous running in wheels for 3-35 days. Blood samples were collected after 3, 7, 14, 21 and 35 days of exercise and all samples were drawn after the running wheel had been locked during the preceding 12 h. The plasma nitrate level was significantly (P < 0.05) elevated in SHR after 35 days of exercise. Surprisingly after 7 days of exercise a significant (P < 0.001) decrease in the nitrate level in plasma was noted. Further research is needed to elucidate this biphasic change in nitrate seen in this study. The elevated level of plasma nitrate seen after 35 days of voluntary exercise was still present up to 36 h after termination of exercise. We conclude that exercise training in SHR elicits an enhanced formation of NO.
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