logged stand of trees. 21. Lltterial data from (S), ndcate that t t e r f a lnputs of carbon are between about 50 and 120 g m-'year-' for coniferous forests of the Slerra transect above 1200 m eevaton We estimated carbon productivity for grasses at the Fabrook slte by assumng that ther v a l~~e s are smlar to those for other grassland soils In Cafornla (between 50 and 100 g m-' y e a r 1 [R. Vaentn et a1 , Ecology 76 1940 (1 995)] 22 D. C. Nepstad e i a/. , i~laiure 372 666 (I 994) 23 S E Trumbore er a1 , Global Biogeochem Cycles 9. 515 (1995). 24. W M Post era/., Nature 298, 156 (1 982); D. S. Jenklnson, D E Adams, A. W11d /bid 351,304 (1991), A. R. Townsend eta/., Chm Change 22, 293 (1992). 25. M. Klrschba~lm So11 Blol. Biochem. 27, 753 (1 995). 26. The est~mates of carbon change In Fig. 3 Ignore important factors, such as probable changes n carbon inputs to the soil by plants and feedbacks be-tween SOM decomposton and plant productivity, In additlon the climate transects studled ~n H a w a and the Serra Nevada Integrate long-term adj~~stment of ecosystems to average cllmatic cond~t~ons, and translent responses may not be predctabe from the temperature-turnover relations derlved here However, soil incubations and sol respratlon measurements have shown that on short t m e scales, carbon fluxes from soils are strongly dependent on temperature, with Ql , values ranglng from 2 to 5 [J. W. Rach and W. H. Schesnger, Tellus 448, 81 (1 992); D W. Klckghter er a/., J. Geophys Res. 99, 1303 (1 994)] (25) In accord with values, derlved from F g 2, of 3 0 to 3 8. [Q,, 1s the rateoia b i o o g c a process (here, decompositon) at one temperatwe divded by the rate of the process at a temperature 10°C cooler ] 27.

No abstract

The growth of continuous adherent diamond thin films on optically transparent substrates is important for the development of corrosion and erosion resistant infrared windows for many applications. Until now, the growth of adherent diamond films on optically transparent substrates like sapphire has been unsuccessful due to the large thermal mismatch between the film and the substrate and the absence of an interfacial carbide ‘‘glue’’ layer. By employing a low temperature (500–550 °C), low pressure (∼1 Torr) electron–cyclotron–resonance chemical-vapor-deposition process, and utilizing a dispersed–particulate diamond suspension for nucleation, adherent diamond thin films have been fabricated on sapphire substrates. Raman spectroscopy showed that the diamond peak was shifted approximately 6 cm−1 above its equilibrium position, suggesting the presence of very large compressive stresses (∼3.2 GPa) in the film.

No abstract

We have deposited diamond thin films remote from the active plasma region using an electron cyclotron resonance chemical vapor deposition technique. Diamond films were fabricated at temperatures in the range of 550–650 °C and gas pressures between 25 and 60 mTorr. The volume ratio of water to methanol was varied from 1:20 to 1:5 to optimize diamond film growth. High methanol content resulted in multiple nucleation in the growing diamond film, while higher water content led to complete etching of the film. A positive electrical bias was found to be essential for diamond thin film growth remote from the plasma region. The films were characterized by x-ray diffraction, micro-Raman, and scanning electron microscopy for phase identification, surface morphology, and bonding characteristics.