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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 3237-3241 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We deposit compact amorphous hydrogenated silicon (a-Si:H) films at 50 °C, using low silane partial pressures in silane/hydrogen reaction mixtures. The 29Si chemical shift and infrared signature of our films are strongly affected by the silane feed partial pressure, but are insensi- tive to the hydrogen feed partial pressure, indicating that hydrogen "etching'' does not play a significant role in the film growth process. Interestingly, the 29Si chemical shift and infrared signature of our compact 50 °C films are similar to those of a-Si:H films deposited at standard "optimum'' conditions, but the electronic properties are very different. Upon thermal annealing at 150 °C for 3 h, the spin defect density may be reduced by as much as 2 orders of magnitude, while the hydrogen content, 29Si chemical shift and infrared signature remain unchanged. Therefore, it seems possible to first grow a compact silicon network structure in a-Si:H at 50 °C, and then equilibrate the electronic structure at 150 °C, without significantly altering the silicon network.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 7 (1995), S. 904-911 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Batch sedimentation experiments were conducted with suspensions of noncolloidal spherical particles. Using nuclear magnetic resonance imaging (NMRI), the time evolution of the volume fraction versus height profile was measured for initial suspension volume fractions, φi, ranging from 0.08 to 0.44. NMRI clearly delineates the clear fluid layer at the top of the suspension, below which there is a transition to a region having the initial mean particle concentration. The hindered settling function determined from these data corresponds well with previous results. The spreading of the interface in excess of that expected from the combined effects of polydispersity and self-sharpening was analyzed as a diffusion process. The measured values of the self-induced hydrodynamic diffusivity agreed with those reported previously, and they decreased sharply for φi(approximately-greater-than)0.15. The concentration profile was also measured through the fan region into the sediment, where the volume fraction is near maximum packing, and determined the fan thickness as a function of time. The fan thickness is found to increase as the initial suspension volume fraction is increased. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1572-9699
    Keywords: Polyhydroxyalkanoate ; Pseudomonas stutzeri
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pseudomonas stutzeri strain 1317 was found to grow on various fatty acids, alcohols, diols, as well as glucose and gluconate for the synthesis of polyhydroxyalkanoates (PHA) with various monomer units. The PHA monomer structures were dependent on the type of fatty acids and alcohols, as well as the diols in the culture media. Only even number monomers, such as 3-hydroxyhexanoate (HHx), 3-hydroxyoctanoate (HO) and 3-hydroxydecanoate (HD), were accumulated when even numbered fatty acids, alcohols, glucose and gluconate, as well as diol were used as carbon sources. Odd numbered fatty acids and odd numbered alcohols led to the formation of odd numbered monomers, such as 3-hydroxyvalerate (HV), 3-hydroxyheptanoate (HHp), 3-hydroxynonanoate (HN) and 3-hydroxyundecanoate (HU). The strain tolerated up to 1.5% of ethanol and made 8.3% of PHA when growth was conducted in 1.2% of ethanol. PHA formed up to 77% of cell dry weight when the strain was grown in tridecanoate. PHA synthesis was highly dependent on the nitrogen source. A depletion in nitrogen supply immediately resulted in PHA accumulation in cells grown in the glucose mineral medium.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 42 (1996), S. 271-276 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 41 (1995), S. 251-257 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Magnetic resonance imaging (MRI) is used to measure the time evolution of the volume fraction vs. height profile during batch sedimentation of rod-like particle suspensions. At any instant during sedimentation, MRI clearly delineates the supernatant, suspension, and sediment regions. The rod-like particles with a mean aspect ratio of 17.4 exhibit considerably larger hindered settling effects than spherical particles with increasing particle concentrations. This can be attributed in part to the larger increase in interparticle forces and relative viscosities with suspensions of rod-like particles than with suspensions of spherical particles, as the particle concentration increases. The relative viscosity of the rod-like particle suspensions is a function of the spin-spin relaxation time, T2. Since T2 is a measurable MRI quantity, this suggests that MRI may be used as an instrument for rheological measurement.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 43 (1997), S. 2596-2600 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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