Modeling and Experimental Verification of SiC M-PVT Bulk Crystal Growth

2006 ◽  
Vol 527-529 ◽  
pp. 75-78 ◽  
Author(s):  
Peter J. Wellmann ◽  
Ralf Müller ◽  
Michel Pons

We have studied the impact of the chemical nature of additional gases fed into the modified physical vapor transport (M-PVT) growth cell. In particular experiments were carried out using helium, argon, nitrogen and propane in the growth setup. Numerical modeling was used to address the underlying physical and chemical effects that impact the global temperature field. It is found that chemical decomposition of complex gases plays a secondary role as heat source or sink. However, temperature variations related to varying gas compositions fed to the systems are primarily induced by changes of the graphite foam isolation properties.

ALGAE ◽  
2021 ◽  
Vol 36 (3) ◽  
pp. 195-206
Author(s):  
Kevin Erratt ◽  
Irena Creed ◽  
Camille Chemali ◽  
Alexandra Ferrara ◽  
Vera Tai ◽  
...  

Increasing inputs of dissolved organic matter (DOM) to northern lakes is resulting in ‘lake browning.’ Lake browning profoundly affects phytoplankton community composition by modifying two important environmental drivers—light and nutrients. The impact of increased DOM on native isolates of red and green-pigmented cyanobacteria identified as Pseudanabaena, which emerged from a Dolichospermum bloom (Dickson Lake, Algonquin Provincial Park, Ontario, Canada) in 2015, were examined under controlled laboratory conditions. The genomes were sequenced to identify phylogenetic relatedness and physiological similarities, and the physical and chemical effects of increased DOM on cellular performance and competitiveness were assessed. Our study findings were that the isolated red and green phenotypes are two distinct species belonging to the genus Pseudanabaena; that both isolates remained physiologically unaffected when grown independently under defined DOM regimes; and that neither red nor green phenotype achieved a competitive advantage when grown together under defined DOM regimes. While photosynthetic pigment diversity among phytoplankton offers niche-differentiation opportunities, the results of this study illustrate the coexistence of two distinct photosynthetic pigment phenotypes under increasing DOM conditions.


2004 ◽  
Vol 815 ◽  
Author(s):  
Govindhan Dhanaraj ◽  
Feng Liu ◽  
Michael Dudley ◽  
Hui Zhang ◽  
Vish Prasad

AbstractSiC single crystals have been grown by seeded sublimation method using physical vapor transport (PVT) system designed and fabricated in our laboratory. A novel multi-segmented graphite insulation has been used for improved heat containment in the hot-zone. Numerical modeling was used to obtain the temperature field and predict various growth parameters. The grown crystals were characterized using AFM, SWBXT and chemical etching.


1981 ◽  
Vol 51 (3) ◽  
pp. 413-425 ◽  
Author(s):  
D.W. Greenwell ◽  
B.L. Markham ◽  
F. Rosenberger

2014 ◽  
Author(s):  
Jeffrey J. Swab ◽  
James W. McCauley ◽  
Brady Butler ◽  
Daniel Snoha ◽  
Donovan Harris ◽  
...  

2019 ◽  
Author(s):  
Maria L. Leonard ◽  
◽  
Rachel M. Kelk ◽  
Dori J. Farthing

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