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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 82 (1985), S. 1555-1566 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have used the classical trajectory method to investigate rotationally inelastic encounters between diatomic molecules and a hierarchy of model surfaces: a rigid surface (RS), a simple harmonic oscillator (SHO), and a generalized Langevin oscillator (GLO). The diatom masses correspond to NO throughout, and the gas–surface interaction potential was invariant, with an attractive potential of cursive-epsilon=0.58 or 0.2 eV. Collision energies were 0.3 or 0.7 eV. Encounters were classified as "direct,'' "indirect,'' and "adsorbed.'' Change from the RS to the SHO surface markedly increased the percentage of indirect encounters; change from SHO to GLO introduced adsorbed trajectories. Rainbow structure in the product rotational distribution, clearly evident on the RS, was obscured by the surface motion in the SHO and GLO models, remaining evident nonetheless for the higher collision energy. Sticking on the GLO surface decreased with increasing initial rotation, particularly for the weaker attractive potential. Consequently application of time-reversal symmetry led to a yield of desorbing molecules weighted toward lower final rotation, i.e., to a rotational temperature TROT〈TS (TS=surface temperature). The need for detailed experimental studies to establish the dynamics is evidenced by the fact that the characteristic bimodal distribution over final rotational states is obtained for all three model surfaces—RS, SHO, and GLO.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 60 (1989), S. 1752-1755 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The electron storage ring BESSY is a primary radiometric standard where the photon flux can be adjusted within a dynamic range of 12 orders of magnitude via the stored beam current IR. We describe the three different devices installed at BESSY to perform the measurement of the absolute beam current within the full range. Two toroidal dc beam current transformers are used in the range 0.5 mA〈IR〈1 A. The measurement of lower beam currents is based on monitoring the emitted white synchrotron radiation flux. If less than 1000 electrons are stored (IR〈0.8 nA) then electron counting is performed. In the intermediate range (0.8 nA〈IR〈1 mA), IR is determined via windowless photodiodes which have been calibrated against the transformers and against the single electron measurements which allow a check of the linearity of the detectors. We report on the calibration procedure, on influences of changes of the source, and on the resultant uncertainties.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary. An examination of the maternal vascular response to placentation shows that physiological changes in the placental bed normally extend from the decidua into the inner myometrium. In pre-eclampsia and in a proportion of pregnancies with small-for-gestational age infants (SGA) the physiological changes are restricted to the decidual segments alone. In addition, complete absence of physiological changes throughout the entire length of some spiral arteries is seen in pre-eclampsia and SGA. This new observation is confirmed in a study of basal plates of placentas from abnormal pregnancies. Intraluminal endovascular trophoblast may be seen in the placental bed spiral arteries in the third trimester in pre-eclampsia and SGA, a feature not seen beyond the second trimester in normal pregnancy. These findings point to a defect in the normal interaction between migratory trophoblast and maternal uterine tissues in pre-eclampsia and in SGA.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 94 (1987), S. 0 
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1437-160X
    Keywords: Reticuloendothelial system clearance ; Immune complexes ; Plasmapheresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The nonspecific clearance function of the reticuloendothelial system (RES) in six patients with immune complex mediated systemic vasculitis was determined by the evaluation of the disappearance rate of technetium 99m labelled microaggregated human serum albumin colloid (MHAC) injected IV before and after therapeutic plasma exchange. Three patients with systemic lupus erythematosus (SLE) and one patient with immune complex vasculitis (ICV) exhibited a significant clinical improvement after plasmapheresis which was paralleled by an accelerated MHAC elimination rate following plasma exchange therapy. One patient with ICV and unresponsive to plasma exchange showed delayed MHAC elimination. In one patient with myasthenia gravis (MG), the elimination rate was not altered by plasmapheresis. The data obtained indicate that nonspecific clearance of the RES may be one effect of plasma exchange therapy in patients with immune complex mediated diseases.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Reaction kinetics and catalysis letters 34 (1987), S. 129-135 
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Исследовано влияние силилирования гексаметилдисилазаном на адсорбционные и каталитические свойства платиновых катализаторов, нанесенных на пористое стекло. Найдено, что каталитическая активность значительно уменьшается с увеличением заполнения поверхности триметилсилильными группами для всех следующих реакций: гидрогенизации бензола, дегидрогенизации циклогексана и дегидроциклизации н-гексана.
    Notes: Abstract Effect of silylation with hexamethyldisilazane on adsorption and catalytic properties of porous glass-supported platinum catalysts has been studied. Catalytic activity decreases markedly with an increase in surface coverage by trimethylsilyl groups for all the following reactions examined: hydrogenation of benzene, dehydrogenation of cyclohexane and dehydrocyclization of n-hexane.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The indentation microhardnessMH of high-density polyethylene crystallized at different pressuresp and crystallization ratesν c has been investigated. The results confirm thatMH is an increasing function of lamellar thickness and therefore of densityρ. The rate of increase depends on the crystallization conditionsp andν c. Crystallization at high pressure leads toMH values considerably higher than those of samples prepared under atmospheric pressure. The results are discussed in terms of compressed amorphous regions contributing to an elastic release after removal of the indenter. For samples crystallized under different pressures the hardness value turns out to be nearly independent of the elastic modulusE. For samples crystallized at different ratesν c there is a steady decrease of microhardness with increasingν c (decrease of lamellar thickness) but no simple relationship withE. With higher ratesν c the appearance of strained tie molecules provokes a rapid increase ofE whileMH decreases further because the crystals become smaller.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 329 (1987), S. 483-492 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Bipolar Ion Exchange ResinsSyntheses of weakly acid/strongly basic and weakly acid/weakly basic bipolar ion exchange resins with varying acid and basic capacities via subsequent introduction of the exchange active groups in suitable crosslinked skeletal polymers are described.Methylacrylate-styrene-divinylbenzene polymers of varying composition which can be quantitatively chloromethylated and subsequently fully aminated (trimethylamine) and partially saponified in one process step were used as starting polymers for weakly acid/strongly basic resins. The reverse route saponification of the ester groups first, followed by chloromethylation of the aromatic parts of the matrix and animation turned out to the possible, if at all, only for bipolar resins of strongly predominant basic character. The capacity parameters can be controlled through the composition of the matrix.Polymethylacrylates crosslinked with divinylbenzene served as polymer basis of the weakly acid/weakly basic bipolar ion exchange resins. The functionalization was achieved by partial aminolysis with polyamines (dimethylaminopropylamine, ethylenediamine, diethylenetriamine) and saponification with lyes. The number of basic and acid groups which can be introduced is governed primarily by the conditions of the aminolysis. The capacity parameters are controllable within a broad range by the procedures.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 548 (1987), S. 204-216 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Crystalline Metal Silicate Hydrates of Layer StructureThe purpose of this paper is the synthesis of metal silicate hydrates by means of hydrothermal crystallization from the ternary systems M2/nO—SiO2—H2O (M = Li, Na, K, Ca, Mg). The prepared products, the sodium silicates ilerite, magadiite, and kenyaite and a potassium silicate hydrate, are species of crystallization sequences of a hydrothermal quartz formation process at low temperatures. The product sequences, obtained under different crystallization conditions are given and discussed.
    Notes: Gegenstand der Arbeit ist die Synthese von Metallsilicathydraten (M—SH) mit Schichtstruktur durch hydrothermale Kristallisation im ternären System M2/nO—SiO2—H2O (M = Li, Na, K, Ca, Mg). Die erhaltenen Produkte, die Natriumsilicathydrate Ilerit, Magadiit und Kenyait und ein Kaliumsilicathydrat sind Bestandteile von Produktfolgen im hydrothermalen Quarzbildungsprozeß bei niedrigen Temperaturen. Die Produktfolgen bei verschiedenen Kristallisationsbedingungen werden angegeben und diskutiert.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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