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  • 1
    ISSN: 1432-2048
    Keywords: Alginate ; Cellulose ; Cell wall ; Crystalline allomorphs ; Hydrodynamics ; Phaeophyta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To test whether secondary and tertiary structures of marine-algal structural polysaccharides may be altered during adaptive responses to hydrodynamic stresses, juvenile Egregia menziesii (Turn.) Aresch. sporophytes were cultured under three different regimes: (i) low-energy (LE) specimens were subjected to water motion produced by standard bubbling and circulation of tank water; (ii) high-energy (HE) specimens received additional movement in pumped streams of water; and (iii) stretched (STR) specimens were grown under low-energy conditions but also were subjected to constant, longitudinal tension (0.7 N). After 6–10 weeks growth, cell-wall structural polysaccharides from specimen blades were isolated by solubilizing less-ordered matrix polysaccharides. Neutral-sugar and uronic acid contents of these isolates were measured, and samples were analyzed by x-ray diffraction and by Raman and 13C-nuclear magnetic resonance (NMR) spectroscopy. On average, structural polysaccharides formed about 7.2% of dry-weight biomass. The portion of isolated mass accountable to neutral sugars ranged from an average of 85% for STR sporophytes to 94% for both LE and HE specimens. For all specimens, glucose composed an average of 99% of this fraction. Uronic acids could not be detected in isolates from any treatment group. Cellulose dominance in each isolate was indicated clearly in x-ray diffraction patterns and in Raman and 13C-NMR spectra. These data further demonstrated that both the cellulose I allomorph and the disordered form of the polymer were present in each isolate and that the STR isolate contained small quantities of the cellulose II allomorph. In general, the LE and HE samples had very similar crystallinity; lateral order was slightly more developed in LE samples. However, the STR treatment produced cellulose with lowest crystallinity and least lateral order. Results suggest that mechanical stress modified cellulose crystallinity in these kelps by altering levels of disordered cellulose and lateral dimensions of cellulose crystallites and, in one instance, changed the crystallinity qualitatively. Physical disturbances to cell plasma membranes may have instigated these trends. In the STR specimens in particular, such disturbances might have been supplemented by fundamental changes to kelp physiology, affecting both substantial decreases in crystallinity and production of the cellulose II allomorph. Changes in the nature of the cellulose cannot, however, account for changes in the elastic moduli.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 246 (Jan. 1997), p. 29-60 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 67 (1931), S. 179-183 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Zusammenfassung Genauere Abgrenzung des Sprödigkeitsbereichs von Eisen bei technischem Material und Einkristallen. Auffindung eines Gebietes des Korngrenzenbruchs innerhalb des innerkristallinen Spaltbruchs.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1436-6215
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary A twenty-four percent solution of carbohydrates 0.2 g/kg/h consisting of fructose, xylit and glucose in a 2/3n1/3n1 ratio and an aminoacid solution 0.03 g/kg/h were given to 13 patients of the internal medicine intensive care unit. There was an unimportant loss of carbohydrates, only, with but few exceptions, i.e. a loss of 11% in 3 patients. The results demonstrate that the carbohydrates of the combined solution become utilized independent of each other. The balance of water, sodium, potassium and magnesium were not only negative but also positive. The elimination of calcium was between 1–19 mval/24 h, of phosphate between 0.6–8.7 mval/24 h.
    Notes: Zusammenfassung Nach intravenöser Dauerinfusion einer Kohlenhydratkombinationslösung, bestehend aus Fruktose, Glukose und Xylit (2/3n1/3n1) mit einer Zufuhrrate von 0,2 g/kg/h und gleichzeitiger Zufuhr von Aminosäuren mit einer Dosierung von 0,03 g/kg/h, fanden sich nur geringe Verluste von Fruktose, Glukose und Xylit. Nur bei 3 Patienten lag der Endverlust über 11%. Die Ergebnisse zeigen, daß unter Anwendung einer Kohlenhydratkombinationslösung die einzelnen Substrate unabhängig voneinander verwertet werden. Die Bilanzen für Wasser, Natrium, Kalium und Magnesium waren teils negativ, teils positiv. Die Ausscheidung von Kalzium bewegte sich zwischen 1 und 19 mval, die von Phosphat zwischen 0,6 und 8,7 mval/24 h.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Experimental astronomy 7 (1997), S. 361-367 
    ISSN: 1572-9508
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Spectrum-UV mission, a general purpose ultraviolet observatory equipped with a 170-cm aperture telescope for imaging and spectroscopy in the 912 to 3600 Å range, will be launched in a seven days, high elliptical orbit in the late '90s by a Proton booster. The German contribution to the focal plane instrument complex is described: HIRDES, a High Resolution Double Echelle Spectrograph.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Space science reviews 30 (1981), S. 575-580 
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Astrophysical plasmas at temperatures in the range (0.5–5)×105 K that occur e.g. in interstellar space, in the extended atmospheres around stars of essentially all spectral types, including the numerous late-type stars with low photospheric temperatures, and in the atmospheres of highly evolved stars, can best be studied at extreme ultraviolet wavelengths where they release the bulk of their energy. We report here the current development status of a 1m-normal-incidence-EUV-telescope that will be flown on an ARIES rocket to observe the spectra of nearby stars in the 350 – 700 mm range.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Soft X-ray photographs of the Sun taken at O vii 21.6 Å and in a spectral band ranging from 13.2 to 22.1 Å have been analysed in order to establish spatially resolved maps of temperature and emission measure for several active regions in the corona. The photographs were taken on 11 March, 1971, and on 2 March, 1972, with Fresnel zone plate cameras which were flown on ESRO and NRL sounding rockets. In Part I of this paper we first deal with those aspects of the instrumentation which are important for setting up a suitable image analysis procedure. We discuss the characteristics of the wavelength dependent image formation by zone plates combined with absorption filters. Results of the calibration of the X-ray film are given. Then we describe a specific iterative data reduction procedure and finally present the resulting maps of temperature and emission measure for a selected active region. In Part II corresponding results for further active regions will be given and discussed.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 73 (1928), S. 247-248 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 24 (1993), S. 131-141 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Arc-PVD-Coating of Cemented Carbides and Analysis of their Functional Behaviour in Interrupted Cut MachiningInterrupted machining of quenched and tempered steel demands the application of tools with high resistance against mechanically and tribologically induced wear. These demands can not be fully satisfied by uncoated carbides. Also CVD-coatings give only some improvement due to a certain embrittlement of the substrate during the coating process. PVD-coatings deposited at low temperatures without affection of the substrate lower the influence of the relevant wear mechanisms preferably at moderate cutting speeds.The combination of tough substrates with structural and compositional optimized coatings results in a multiplication of tool life within the whole range of low and medium cutting speeds. Coatings with homogenious structure, compressive residual stresses and high content of metalloides ensure excellent resistance against wear.Titanium-carbonitride deposited on carbide was found to be superiour compared with other carbonitride, nitride and carbide coatings within the system Ti—Zr—C—N due to excellent tribological properties. It was optimal suited for the interrupted cut application.
    Notes: Die Zerspanung von höherfesten Stahlwerkstoffen in unterbrochenen Schnitten stellt an die Werkzeuge hohe mechanische und tribologische Anforderungen, denen unbeschichtete Hartmetalle in vielen Fällen nicht gerecht werden können. Während sich bei der Zerspanung von höherfestem Stahl in stark unterbrochenen Schnitten durch die CVD-Beschichtung von Hartmetallen auf-grund prozeßbedingter Versprödungseffekte kaum Leistungssteigerungen erzielen lassen, können PVD-Hartstoffbeschichtungen, die bei substratschonend niedrigen Prozeßtemperaturen abgeschieden werden, dem Auftreten der relevanten Schädigungsmechanismen besonders bei niedrigen und mittleren Schnittgeschwindigkeiten entscheidend entgegenwirken.Insbesondere mit zähen Substratsorten sowie mit strukturell und kompositionell optimierten Schichten können Standzeitvervielfachungen im gesamten unteren und mittleren Schnittgeschwindigkeitsbereich erzielt werden. Homogene Schichtstrukturen, hohe Druckeigenspannungen und hohe Metalloidgehalte der Hartstoff-schichten gewährleisten eine hohe Verschleißfestigkeit. Titankarbonitrid zeichnet sich auf Hartmetallen gegenüber anderen karbonitridischen, nitridischen und karbidischen Schichten des Systems Ti—Zr—C—N durch ein besonders günstiges tribologisches Verhalten aus und hat sich als optimaler Beschichtungswerkstoff für unterbrochene Schnitte erwiesen.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
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