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  • 1
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 1815-1817 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A cryogenic refrigeration scheme is presented which utilizes the discrete energy levels of quantum dots to customize the electronic Fermi–Dirac distribution, cooling a small but macroscopic reservoir to far below the ambient temperature. Several physical limitations of this scheme are discussed within the context of a model device constructed from a two-dimensional electron gas. These are explored in a simple example where, at an ambient operating temperature of 150 mK, this quantum-dot refrigerator can achieve a cooling power of 1 μW/cm2, a base temperature of 10 mK, and a cooling efficiency of 35%.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1520-5835
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Nuclear and Particle Science 35 (1985), S. 605-660 
    ISSN: 0163-8998
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 69 (1904), S. 272-272 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] SOME time ago when developing an X-ray photograph I observed the effect noticed by your correspondent in your last issue. Very little of the silver salt had been affected, and the plate, after development, when put into alum solution lit up as described. I have often watched for the same effect ...
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Journal of industrial microbiology and biotechnology 13 (1994), S. 43-48 
    ISSN: 1476-5535
    Schlagwort(e): Milbemycin ; Fructose ; Starch ; Carbon:nitrogen ratio
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Summary Milbemycin production byStreptomyces hygroscopicus RB4569D was examined in media containing different carbohydrates. Total milbemycin titer could be increased by substitution of fructose for glucose and by selection of the appropriate starch type. Total titer could be further enhanced by increasing the concentration of fructose and/or starch in the medium. Rates of carbohydrate utilization were shown to be independent of their initial concentration and increased titers in high carbohydrate media were shown to be due to a prolonged production phase rather than an increased accretion rate. The pattern of individual milbemycin components was governed by the carbon:nitrogen ratio of the medium rather than carbohydrate concentration and there was a critical C:N ratio below which no milbemycin was produced.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    ISSN: 1573-1111
    Schlagwort(e): Force constant calculations ; n-alkanes ; mono-halo and di-halo alkanes ; urea inclusion compounds ; LAM-1 modes ; accordion vibrational modes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Force constants were determined for the C8, C10, C12 and C14 series ofn-alkanes C n H2n + 2 using an approximate SVFF calculation and observed LAM = 1 wave numbers. In this calculation the hydrogen atoms were neglected and only the carbon backbone chain and terminal atoms were considered; this was valid since only low-frequency vibrations were under consideration. Using force constant transfer, the wavenumbers of the LAM = 1 accordion modes for the analogous α-Cn H2n + 1 X and α,ω-Cn H2nX2 species, where X = C1, Br or I were calculated. For α-chloroalkanes and α,ω-dichloroalkanes, them = 1 accordion modes are calculated to be in the 220–130 cm−1 and 200–120 cm−1 regions, respectively. For the bromo- and iodo-analogues them = 1 accordion modes are calculated to be in the 200–100 cm−1, 150–90 cm−1 and in the 170–100, 135–80 cm−1 regions, respectively.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 911-923 
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Three commercial heparins of different molecular weights and anticoagulant activities were dinitrophenylated (DNP) with 2,4-dinitrofluorobenzene under aqueous conditions. The absorption spectra observed for DNP heparins in a 1% NaHCO3 solution consisted of the two absorption spectra characteristic of DNP - amino (N - DNP) and DNP - hydroxyl (O - DNP) groups. The number of N - DNP, O - DNP, and (N + O) - DNP groups were determined as well as the number of N - DNP groups per heparin chain; different values (i.e., 0.16, 0.17, and 0.55) for the latter were obtained with the three heparins. Further calculations showed that two of the heparins had approximately two (N + O) - DNP groups per chain (i.e., 2.1 and 1.8) whilst the third sample, considered to be a “cruder” heparin, had a value of 1.4.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 1497-1503 
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Three different commercial heparins were trinitophenylated with 2,4,6-trinitrobenzenesulfonic acid (TNBS) under aqueous conditions. The reaction kinetics of amino groups in heparin with TNBS showed that the reactivities of amino groups were significantly different for free amino groups on heparin, compared to reactivities in peptides and amino acid residues attached to heparin molecules. With TNBS, unreactive amino groups were always present during the reaction.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 247 (1987), S. 121-128 
    ISSN: 1432-0878
    Schlagwort(e): Neural repair ; Glia ; Cell deployment ; Haemocytes ; Scanning electron microscopy (SEM) ; Insect (Periplaneta americana)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In Periplaneta americana, SEM of abdominal nervous connectives revealed a rapid accumulation of haemocytes on the surface of the neural lamella within 24 h of selective disruption of the underlying neuroglia by ethidium bromide. After 4 days the neural lamella was effectively clear of adhering haemocytes, but showed characteristic “blisters”, which, it is postulated, represented the points of entry of the cells from the haemocoel into the underlying tissues. A notable subsequent feature was a substantial increase in the number of cells within repairing connectives. Initially, there was a marked asymmetry in their distribution, with significantly higher numbers of cells anterior to, and within, the lesion area. It seems likely that this polarity resulted from differential cell division within the connectives. The initial asymmetry disappeared after seven days. However, increased perineurial cell numbers were maintained in the lesion area after one month and were still apparent two months after selective glial disruption. There was no equivalent increase in cell numbers in the lesion zone of cultured cords or, in vivo, after injection of the DNA-scission drug, bleomycin, treatments which preclude haemocyte involvement. It is suggested that in the absence of haemocytes and with suppression of proliferation by endogenous cells, repair is achieved by redeployment or growth of adjacent, undamaged glia.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 22 (1991), S. 607-611 
    ISSN: 0377-0486
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The pressure-broadening coefficients for the self-broadened S0(0), S0(1) and S0(2) pure rotational Raman lines of hydrogen and the S0(0) to S0(4) lines of deuterium were determined experimentally over the pressure range 1-100 bar and the temperature range 90-375 K. Broadening coefficients were also determined for the same lines in hydrogen and deuterium perturbed by helium, argon, oxygen, nitrogen, carbon monoxide and hydrogen chloride over the pressure range 2-100 bar, with a partial pressure of the host gas of 1 bar and a temperature of 293 K. In addition, the S0(0) pure rotational line of deuterium broadened by carbon monoxide and nitrogen was studied over the same pressure range and a temperature range of 100-293 K. The results are discussed and compared with those of previous studies in the literature.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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