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  • 1
    Digitale Medien
    Digitale Medien
    Equilibrium distribution of lithium and bismuth between liquid lithium-bismuth alloys and molten lithium chloride at 650-800.deg. (1973)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 77 (1973), S. 2351-2357 
    Details
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/j100638a018
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  • 2
    Digitale Medien
    Digitale Medien
    Thermal stability of diamondlike carbon films (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 3068-3075 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: IR and UV-VIS optical spectroscopy have been used to study the transformations of the properties of diamondlike carbon films following isothermal anneals from Ta=300 to 650 °C. Several processes due to the annealing have been observed: (1) the increase of the absorption due to vibrations of unsaturated bonds of C(sp2) atoms at ∼1600 cm−1 for Ta≥350 °C, (2) the decrease of the absorption due to C(sp3)–H bonds at Ta≥350 °C, and (3) the reduction of the optical energy gap. Analysis of the kinetics has shown that the dehydrogenation of the alloys and the formation of unsaturated bonds may proceed independently. The reduction of the energy gap is related to the formation of C(sp2) atoms with unsaturated bonding which occurs mostly in hydrogen-free regions. Intensive graphitization of the films occurs above Ta=650 °C. Transformations of C–H bonds are proposed to occur via fast rearrangement in stressed regions leading to formation of new C(sp2)–H bonds and formation of methane molecules as the most important product of the anneals inside the polymeric highly hydrogenated regions in the alloys. It appears that both bond removal and reordering have taken place as a result of annealing. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.363167
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  • 3
    Digitale Medien
    Digitale Medien
    Atomic bonding in amorphous carbon alloys: A thermodynamic approach (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 2954-2967 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The free energy model previously developed for the prediction of the bonding in amorphous Si-based alloys is extended here to amorphous carbon alloys, a-CxH1−x, containing carbon atoms with sp3 and sp2 hybridization. Predictions have been made for the bonds present in the alloys, with the case of "chemical'' ordering at T=0 K corresponding to phase separation into separate C (sp3) and C(sp2) regions. For T(approximately-greater-than)0 K phase separation is eliminated and there is no evidence for the clustering of graphitic carbon, indicating the importance of the configurational entropy in influencing the bonding in the alloys. Hydrogen atoms are predicted to bond preferentially to C (sp3) atoms for all T. The sp3/sp2 ratio is predicted to increase with increasing H content, as observed experimentally, and also with increasing T due to entropy effects. Predictions have been made for the distribution of bonds in tetrahedral C(sp3)- and planar C(sp2)=C(sp2)-centered units. It is found that essentially no aromatic or graphitic structures are present in typical alloys. The a-CxH1−x alloys have been proposed to consist of five amorphous components: diamondlike, graphitic, polymeric, olefinic, and mixed diamond–graphitic (d–g) components. It is predicted that the polymeric and mixed d–g components dominate in typical plasma-deposited alloy films while the mixed d–g component dominates in hydrogen-free a-C films. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.361292
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  • 4
    Digitale Medien
    Digitale Medien
    Fluorides and Man (1968)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Pharmacology 8 (1968), S. 395-408 
    Details
    ISSN: 0362-1642
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Medizin , Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.pa.08.040168.002143
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  • 5
    Digitale Medien
    Digitale Medien
    Nuclear magnetic resonance imaging—a new look at the fetus (1985)
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 92 (1985), S. 0 
    Details
    ISSN: 1471-0528
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Summary. A new form of obstetric imaging using nuclear magnetic resonance (NMR) has been assessed for use in pregnancy. A total of 92 examinations were performed in 62 women during the second and third trimesters in both normal and complicated pregnancies including 14 with diabetes, six with pre-eclampsia and four with intrauterine growth retardation. Our experience has shown that NMR imaging gives excellent differentiation of both maternal and fetal tissues, and because of complete penetration both superficial and deep structures have been clearly identified. The best fetal images were obtained most consistently in the third trimester providing good detail of brain, lungs, liver, heart, bladder, subcutaneous fat, placenta and umbilical cord while maternal tissues were clearly seen at all gestations. As this form of imaging uses no ionizing radiation it offers an alternative means with unique capabilities for investigating pregnancy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1471-0528.1985.tb02997.x
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  • 6
    Digitale Medien
    Digitale Medien
    CARBOXYMETHYLCELLULOSE (1952)
    s.l. : American Chemical Society
    Industrial & engineering chemistry 44 (1952), S. 2803-2812 
    Details
    ISSN: 1520-5045
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ie50516a016
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  • 7
    Digitale Medien
    Digitale Medien
    Optical constants of an a-Si1−xCx:H film (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 582-587 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The real and imaginary parts n and k of the index of refraction of a carbon-rich hydrogenated amorphous silicon-carbon alloy film (a-Si1−xCx:H, x∼0.87) have been determined for photon energies between 1.5 and 4.75 eV from measurements of reflectance R and transmittance T. The optical energy gap parameter Eopt has been determined from the energy dependence of ε2=2nk, the imaginary part of the dielectric constant. Depending on assumptions involving the energy dependencies of valence- and conduction-band densities of states and optical matrix elements, values of Eopt ranging from 1.65 to 2.5 eV have been obtained for the as-deposited film (Td=250 °C). Independently of such assumptions, Eopt is observed to decrease to zero as the film is annealed. These results are consistent with enhanced tetrahedral coordination and demonstrate improved thermal stability for this silicon-carbon alloy film as compared to an hydrogenated amorphous carbon film. The density of the film increased from 1.51 to 1.88 g/cm3 with annealing up to 850 °C.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.336616
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  • 8
    Digitale Medien
    Digitale Medien
    Magnetic study of carbon chars in the transition range (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 58 (1985), S. 2681-2685 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Using static techniques, we have measured the susceptibility and magnetization of carbon chars heat treated at temperatures between 1000 and 1500 °C, the so-called "transition range,'' where equivalent information is unavailable by electron spin resonance measurements due to severe line broadening effects. A small increase is observed in the Curie contribution to the susceptibility as a function of heat-treatment temperature, indicating the appearance of unpaired spins possibly associated with structural changes which occur in the transition range. The diamagnetism of these chars increases rapidly with increasing heat-treatment temperature, and a strong temperature dependence appears which is consistent with behavior expected for a two-dimensional gas of charged carriers. The latter can be ascribed to the formation and growth of microcrystalline graphitic regions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.335903
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  • 9
    Digitale Medien
    Digitale Medien
    Coherent millimeter-wave generation by heterodyne conversion in low-temperature-grown GaAs photoconductors (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 1480-1484 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: An analysis has been carried out of optical heterodyne conversion with an interdigitated-electrode photomixer made from low-temperature-grown (LTG) GaAs and pumped by two continuous-wave, frequency-offset pump lasers. The analytic prediction is in excellent agreement with the experimental results obtained recently on a photomixer having 1.0-μm-wide electrodes and gaps. The analysis predicts that a superior photomixer having 0.2-μm-wide electrodes and gaps would have a temperature-limited conversion efficiency of 2.0% at a low difference frequency, 1.6% at 94 GHz, and 0.5% at 300 GHz when connected to a broadband 100 Ω load resistance and pumped at hν=2.0 eV by a total optical power of 50 mW. The predicted 3-dB bandwidth (193 GHz) of this photomixer is limited by both the electron-hole recombination time (0.6 ps) of the LTG-GaAs material and the RC time constant (0.5 ps) of the photomixer circuit.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.353222
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  • 10
    Digitale Medien
    Digitale Medien
    The Constitution of Carob Gum (1948)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 70 (1948), S. 3249-3253 
    Details
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ja01190a013
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