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81.
82.
The conditions of fabrication and the physicomechanical properties of glass-reinforced plastics based on polysulfone combined in different ratios with epoxy resin and Rolivsan were investigated. It was found that realization of the strength of the fibers in glass-reinforced plastics based on three types of binders and mixtures of them at room temperature is approximately the same. The lower strength of glass-reinforced plastics based on polysulfone is determined by the lower concentration of fibers. Modification of thermosetting plastics with polysulfone significantly increases (by 5–8 times) the specific energy of delamination of the glass-reinforced plastics G1c, which should be manifested by an increase in their crack resistance and other operating characteristics. Modification of ED-20 with polysulfone and polysulfone with Rolivsan significantly increases the glass transition temperature of the polymer and affects the character of the temperature curves of the strength of the glass-reinforced plastics.Institute of Chemical Physics, Russian Academy of Sciences, Moscow. D. I. Mendeleev Russian Chemical Technological University, Moscow. Translated from Mekhanika Kompozitnykh Materialov, No. 1, pp. 111–117, January–February, 1996. 相似文献
83.
Dietmar Köther Adalbert Beyer 《International Journal of Infrared and Millimeter Waves》1986,7(7):1037-1045
In this paper a rigorous method is presented which allows a complete calculation of all modes existing on a unilateral finline with an arbitrarily located slot. Also an investigation of the field distribution is possible. Hereby the behaviour of the different modes can be explained. This method also permits the determination of the propagation properties of higher order modes; thus information is needed for the calculation of finline discontinuities. 相似文献
84.
Anhydrous Rare-Earth Acetates, M(CH3COO)3 (M = Sm? Lu, Y) with Chain Structures. Crystal Structures of Lu(CH3COO)3 and Ho(CH3COO)3 Single crystals of the anhydrous rare-earth acetates containing lutetium (type 1) and holmium (type 2) were obtained by crystallisation at 120°C from diluted acetic acid solutions of their oxides and cesium acetate. The crystal structures [Lu(CH3COO)3: orthorhombic, a = 825.85(8), b = 1 398.1(2), c = 823.9(1) pm, Vm = 143.24(3) cm3/mol, space group Ccm21 (No. 36), Z = 4, R = 0.035, Rw = 0.030; Ho(CH3COO)3: monoclinic, a = 1 109.1(3), b = 2 916.3(10), c = 786.8(2) pm, β = 131.90(1)°, Vm = 142.58(8) cm3/mol, space group C2/c (No. 15), Z = 8, R = 0.039, Rw = 0.039, Rw = 0.026] were determined from four-circle diffractometer data sets. The structures consist of one-dimensional infinite chains built up by bridging acetate ions. Ho3+ is coordinated by 8 oxygen atoms, whereas Lu3+ has only 7 nearest oxygen neighbours. The chains are stacked parallel to the [001] direction. Isotypic compounds with Tm? Lu (type 1) and Sm? Er, Y (type 2) were prepared as powders and characterized by X-ray powder patterns. Thermoanalytical investigations (DTA, Guinier-Simon technique) of all compounds have shown that there is a first-order phase transition at 180°C (type 2) and in the range of 230–255°C (type 1). The high-temperature phase crystallizes with the known Sc(CH3COO)3 structure (type 0) where the rare earth cations are surrounded by 6 oxygen atoms. In the case of the type 1 compounds the phase transition is reversible. 相似文献
85.
Robert Klement und Adalbert Kühn 《Fresenius' Journal of Analytical Chemistry》1956,152(1-3):146-153
Zusammenfassung Es wird die Trennung von Arsen, Antimon und Zinn mittels Anionenaustausches mit Hilfe der Thio-Anionen beschrieben. Die vom Austauscher in der OH-Form gebundenen Thio-Anionen der drei Elemente werden durch Kalilauge steigender Konzentration in der Reihenfolge Zinn (0,5 n), Arsen (1,2 bzw. 2,5 n) und Antimon (3,5 n) eluiert. — Die Trennung von Arsen und Antimon ist mit Hilfe der Oxo-Anionen an einem Anionenaustauscher in der Sulfatform möglich. — Es wird auf die Möglichkeit der Trennung des Germaniums von Arsen bzw. von Antimon in Form der Thio-Anionen mit einem Anionenaustauscher in der OH-Form hingewiesen.Herrn Prof. Dr. A. Kurtenacker zum 70. Geburtstag gewidmet.Diplomarbeit A. Kühn, Universität München, März 1956. 相似文献
86.
Zbigniew Grobelny Adalbert Maercker Janusz Kasperczyk 《Journal of organometallic chemistry》2004,689(9):1580-1585
The structure of vinyl ethers determines the direction of the C-O bond cleavage by alkalide K−, K+(15-crown-5)21. Highly reactive organopotassium compounds are intermediate products formed in the system containing phenyl vinyl ether, butyl vinyl ether, ethylene glycol butyl vinyl ether or triethylene glycol methyl vinyl ether. Vinylpotassium and butylpotassium react with 15-crown-5. The oxacyclic ring of the latter is opened in this case. Organopotassium ethers possessing CH2CH2O units eliminate ethylene. It results in various potassium alkoxides. The reaction of 1 with butyl vinyl ether occurs very slow as compared to other vinyl ethers and most of other reagents used till now. 相似文献
87.
Gregianini TS da Silveira VC Porto DD Kerber VA Henriques AT Fett-Neto AG 《Photochemistry and photobiology》2003,78(5):470-474
The effects of ultraviolet (UV) radiation on chlorophyll content and accumulation of the anti-inflammatory monoterpene-indole alkaloid brachycerine in plants and calli of Psychotria brachyceras (Rubiaceae) were investigated. In this study, we also investigated a protective role for brachycerine against stress conditions. Calli and tip cuttings incubated in nutrient media were daily supplemented with 4 or 16 h of UV. High-performance liquid chromatography analyses of methanolic extracts showed only traces of brachycerine in irradiated aseptic cultures, with no alkaloid being observed in control calli. In cuttings, a 10-fold increase in brachycerine content was seen after exposure for 16 h to UV-C, whereas a 4 h daily supplementation doubled the amount of the alkaloid in leaves. Exposure to a UV-B source also doubled the alkaloid yield. In vitro brachycerine was able to quench singlet oxygen. The data indicate a potential protective role for brachycerine against UV radiation, acting as a UV filter (absorption peaks are within the UV range) and a reactive oxygen species scavenger. In addition, UV radiation may be used to increase yields of this compound of pharmaceutical interest. 相似文献
88.
Harald Günther Oswald Eppers Heike Hausmann Dietmar Hüls Hans-Egbert Mons Klaus-Dieter Klein Adalbert Maercker 《Helvetica chimica acta》1995,78(8):1913-1932
The solution structure and the aggregation behavior of (E)-2-lithio-1-(2-lithiophenyl)-1-phenylpent-1-ene ( 1 ) and (Z)-2-lithio-1-(2-lithiophenyl)ethene ( 2 ) were investigated by one- and two-dimensional 1H-, 13C-, and 6Li-NMR spectroscopy. In Et2O, both systems form dimers which show homonuclear scalar 6Li,6Li spin-spin coupling. In the case of 2 , extensive 6Li,1H coupling is observed. In tetrahdrofuran and in the presence of 2 mol of N,N,N′,N′-tetramethylethylylenediamine (tmeda), the dimeric structure of 1 coexists with a monomer. The activation parameters for intra-aggregate exchange in the dimers of 1 and 2 ( 1 (Et2O): ΔH≠ = 62.6 ± 13.9 kJ/mol, ΔS≠ = 5.8 ± 14.0 J/mol K, ΔG≠(263) = 61.1 kJ/mol; 2 (dimethoxyethane): ΔH≠ = 36.9 ± 6.5 kJ/mol, ΔS≠ = ?61 ± 25 J/mol K, ΔG≠(263) = 54.0 kJ/mol) and the thermodynamic parameters for the dimer-monomer equilibrium for 1 (ΔH°; = 26.7 ± 5.5 kJ/mol, ΔS° = 63 ± 27 J/mol K), where the monomer is favored at low temperature, were determined by dynamic NMR studies. 相似文献
89.
Bogdan?Beirowski Robert?Adalbert Diana?Wagner Daniela?S?Grumme Klaus?Addicks Richard?R?Ribchester Michael?P?ColemanEmail author 《BMC neuroscience》2005,6(1):6
Background
The progressive nature of Wallerian degeneration has long been controversial. Conflicting reports that distal stumps of injured axons degenerate anterogradely, retrogradely, or simultaneously are based on statistical observations at discontinuous locations within the nerve, without observing any single axon at two distant points. As axon degeneration is asynchronous, there are clear advantages to longitudinal studies of individual degenerating axons. We recently validated the study of Wallerian degeneration using yellow fluorescent protein (YFP) in a small, representative population of axons, which greatly improves longitudinal imaging. Here, we apply this method to study the progressive nature of Wallerian degeneration in both wild-type and slow Wallerian degeneration (WldS) mutant mice. 相似文献90.
Adalbert E. Wohanka 《Zeitschrift für Physik A Hadrons and Nuclei》1973,258(3):251-262
Investigating the optical isotropic scintillators KJ (Tl), CsJ (Tl) and plastic NE 102 A a non-vanishing degree of polarization of the emitted light was found. Since the arrangement is otherwise symmetrical, this polarization is only due to the mechanism of activation by deuterons of 27.5 MeV energy. Measurements of fluorescence light emitted by anthracene crystals at room temperature showed within the apparative uncertainty no dependence of polarization from the direction of activation. However such a dependence was found at the temperature of liquid air. 相似文献