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  • 1
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Thermal Behaviour of Sulfates. III. The Behaviour of CdSO4 at High TemperatureThe behaviour of CdSO4 was studied by means of high temperature Guinier photographs in the temperature range of 20 to 960°C. Except N-CdSO4 which is the thermodynamically stable modification at STP, there are 3 high temperature modifications (M, H1 and H2-CdSO4) of which only metastable M-CdSO4 can be obtained kineticly stable at room temperature. The lattice constants and the structure type of H1- and H2-CdSO4 were determined. The structure of H1-CdSO4 is closely related with that of N-CuSO4 but in difference of N-CuSO4 it has a superlattice. H1-CdSO4 crystallizes orthorhombic with a325°C = 17.80 Å, b325°C = 7.35 Å, c325°C = 4.84 Å, Z = 8.H2-CdSO4 crystallizes hexagonal with a850°C = 5.01 Å, c850°C = 7.64 Å, Z = 2 in a modified NaKSO4 structure type (space group P 3m 1) with Cd2+ only in the Na+ positions. The temperatur and sequence of transitions as well as the thermal expansion of N- and M-CdSO4 was determined
    Notes: Mit Heizguinieraufnahmen wurde das Verhalten von CdSO4 im Temperaturbereich von 25-960°C untersucht. Außer der bei Raumtemperatur thermodynamisch stabilen Modifikation (N-CdSO4) existieren 3 Hochtemperaturmodifikationen (M, H1 und H2-CdSO4), von denen nur das metastabile M-CdSO4 bei Raumtemperatur kinetisch stabil zu erhalten ist. Metrik und Strukturtyp von H1- und H2-CdSO4 wurden bestimmt. H1-CdSO4 ist mit N-CuSO4 strukturverwandt, besitzt jedoch eine Überstruktur. Es kristallisiert orthorhombisch mit a325°C = 17,80 Å, b325°C = 7,35 Å, c325°C = 4,84 Å, Z = 8. H2-CdSO4 kristallisiert hexagonal mit a850°C = 5,01 Å, c850°C = 7,64 Å, Z = 2 in einem modifizierten NaKSO4-Typ (RG: P 3m 1); Cd2+ nur auf Na+-Punktlagen. Temperatur und Verlauf der Umwandlungen sowie die thermische Dilatation von N- und M-CdSO4 wurden bestimmt.
    Additional Material: 4 Ill.
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  • 2
    ISSN: 1573-0581
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The Tamayo transform fault occurs at the north end of the East Pacific Rise where it enters the Gulf of California. The two deep-tow surveys reported here show that the transform fault zone changes significantly as a function of distance from the spreading center intersections. At site 1, near the intersection, one side of the fault is young and the fault zone is narrow and well-defined. Strike slip occurs in a zone approximately 1-km wide suggesting a correspondingly narrow zone of decoupling between the Pacific and North American plates. On the young side of the strike-slip zone, normal faults occur along shear zones which are 45°–50° oblique to the transform strike. They occur parallel to the short axis of the strain ellipse for transform fault strain here, i.e., perpendicular to the least compressive stress. The transform walls are formed by normal faulting as has been pointed out in previous detailed surveys. Here, however, the age contrast of 2.5 m.y. across the transform valley is apparent in the morphology of the normal fault scarps. While the scarps are steep and well-defined on the young side, the scarps on the older side have gradual 10°–30° slopes and appear to be primarily talus ramps. Apparently, the scarps have been tectonically eroded by continued strike slip activity after the initial stages of normal faulting. Thus, transform valleys should be quite asymmetric in cross-section where there is a significant age contrast and one side is less than approximately 0.5 m.y. old. Also, along older sections of the transform valley walls, normal faulting may not be at all obvious due to degradation of the scarps by tectonic erosion. This phenomenon makes the likelihood of transform faults providing ‘windows’ into the oceanic crust most unlikely except in special cases. The picture of transform deformation is more complex at site 2 in the central portion of the fault where both sides of the fault are greater than 1 m.y. old. Here the transform valley is wider (25–30 km as opposed to 2–5 km). There is no clear simple zone of strike slip tectonics. In fact, the only clear evidence for deformation is the intrusion of magmatic or serpentinite diapirs through the sediments of the transform valley floor. The diapirs have deformed the turbidite layers flooring the valley and in one carefully studied case the turbidite sequence has been uplifted, perched atop the diapir. The pattern of deformation on this outcropping diapir shows radial and concentric fractures which can be modeled by a vertical intrusion circular in plan view. Magnetic studies limit the possible composition to basalt or serpentinite. A 60-km-long median ridge is also likely to be the product of intrusion along the transform fault. The survey at site 2 pointed out the importance of vertical tectonics in the transform valley floor and in particular the importance of diapiric intrusions of either basaltic or serpentinite composition. Based on initial boundary conditions and present tectonic elements in the Tamayo fault zone, a possible history of the mouth of the Gulf of California is outlined. The median ridge was emplaced starting approximately 0.8 m.y. ago by regional extension across the transform fault, the result of ‘leaky’ transform faulting. The diapirs occur along a possible ‘relay’ zone of extension midway along the fault which began approximately 0.15 m.y. ago. The extension in this case is parallel to the trend of the transform fault, is still occurring at present, and may evolve into a true spreading center.
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  • 3
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 2D NMR spectra have been measured at variable temperatures between -100°C and +110°C in a sample of melt crystallized deuterated polyethylene (PE). The line shape could be decomposed into a central part originating from deuterons in the amorphous regions and outer parts from crystalline regions of PE. The “NMR crystallinity” determined from this separation was 72% in agreement with the X-ray crystallinity of 74%. Changes of the crystalline NMR line shape were interperted in terms of oscillations around the chain axis, the r.m.s. oscillation amplitude varying from 5° at 40°C to 12° at 110°C. The central part of the NMR line shape indicates the existence of a “narrow” and a “medium” component due to different motional processes in the amorphous regions.
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  • 4
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Thermal Behaviour of Sulfates. II. On the Thermal Dehydration of ZnSO4 · 7 H2O and the Effect of High Temperature upon Anhydrous ZnSO4The dehydration of ZnSO4 · 7 H2O and effect of high temperature upon unhydrous ZnSO4 was examined by means of continous high temperature Guinier photographs. On heating in air ZnSO4 · 7 H2O decomposes stepwise to ZnSO4 · 6 H2O, to an unknown hydrate, to the monohydrate and finally to N—ZnSO4, which is the thermodynamically stable modification at S.T.P. At about 700°C a reversible transformation to H-ZnSO4 can be observed which can start from N—ZnSO4 or H-ZnSO4, proceeds to the oxide sulfate Zn3O(SO4)2 and finally to ZnO.ZnSO4 · 6 H2O crystallizes monoclinically in the hexahydrite structure with a25°C = 9.981 Å, b25°C = 7.250 Å, c25°C = 24.280 Å, β25°C = 98.45°, Z = 8, space group: C 2/c. Cubic H-ZnSO4 is the first A2+B6+O4 compound of H-Cristobalit structure; probable space group F 43 m with a700°C = 7.18 Å, Z =4, N-Zn3O(SO4)2 is monoclinic probable space group B 2 with a25°c=13.987 Å, b25°c=6.706 Å, c25°c =7.379 Å β25°c=90.69°, Z=4, Above 420°C N-Zn3(SO4)2 becomes orthorhombic where at first of all H′-Zn3O(SO4)2 which has a reversible transformation point to H-Zn3O(SO4)2 at 655°C is formed. The probable space group of H-Zn2O(SO4)2 is C 2221 with a 850°C = 7.36 Å, b350°C = 13.96 Å, c850°C = 6.79 Å Z = 4, The solid solution N—Cu1,5Zn1,5O(SO4)2 is isotypic with N—Zn3O(SO4)2 and has the lattice constants a25°C = 14.03 Å, b25°C = 6.62 Å, c25°C = 7.33 Å, β25°C = 90.58°, Transoformations into the non quenchable high temperature modifications H-ZnSO4, H′-Zn3O(SO4)2 and H-Zn3O(SO4)2 are displacive. The thermal expansion of N-ZnSO4 and H-ZnSO4 and H-ZnSO4 has been exa-mined.
    Notes: Mit kontinuierlichen Heizguinieraufnahmen wurde die Dehydratisierung von ZnSO4 · 7 H2O und das Hochtemperaturverhalten von wasserfreiem ZnSO4 untersucht. Der Abbau von ZnSO4 · 7 H2O verläuft an der Luft über das 6-Hydrat, eine unbekannte Hydratphase und das 1-Hydrat zum N-ZnSO4, der Normaltemperaturform; bei etwa 700°C wird die reversible Umwandlung in H-ZnSO4 beobachtet. Die Thermolyse, die von N-ZnSO4 oder H-ZnSO4 ausgehen kann, verläuft über das Oxidsulfat Zn3O(SO4)2 weiter zum ZnO.ZnSO4 · 6 H2O kristallisiert monoklin im Hexahydrit (MgSO4 · 6 H2O)-Typ mit a25°C = 9,981 Å b25°c = 7,250 Å, c25°C = 24,280 Å, β25°C = 98,45°, Z = 8, RG: C 2/c. Das kubische H-ZnSO4 ist die erste A2+B6+O4-Verbindung mit H-Cristobalit-Struktur; wahrscheinliche RG: F 43 m mit a700°C = 7,18 Å, Z = 4. N—Zn3O(SO4)2 ist monoklin mit der wahrscheinlichen RG: B 2 mit a25°C = 13,987 Å b25°C = 6,706 Å, c25°C = 7,379 Å, β25°C = 90,69°, Z = 4. Oberhalb 420°C wird das Oxidsulfat orthorhombisch, wobei zunächst H′-Zn3O(SO4)2 entsteht, das bei 655°C reversibel in H-Zn3O(SO4) übergeht. Für H-Zn2O(SO4)2 ist die wahrscheinliche RG: C 2221 mit a850°C = 7,36 Å, b 850°C = 13,96 Å, c850°C = 6,79 Å, Z = 4. Der Mischkristall N—Cu1,5 Zn1,5O(SO4)2 ist isotyp mit N-Zn3O(SO4)2 und besitzt die Gitterkonstanten a25°C = 14,03 Å, b25°C = 6,62 Å, c25°C = 7,33 Å, β25°C = 90,58°, Z = 4. Die Umwandlungen in die nicht abschreckbaren Hochtemperaturformen (H-ZnSO4 H'-Zn3O(SO1)2 und H-Zn3O(SO4)2) erfolgen displaziv. Die thermische Dilatation von N-ZnSO4 und H-ZnSO4 wurde ermittelt.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 132 (1979), S. 271-276 
    ISSN: 1432-1076
    Keywords: Exostoses ; Benign osteochondromas ; Bone tumors ; Radiation therapy ; Radium-224 ; Thorium X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Exostoses are benign cartilaginous tumors of bone. They can occur naturally or be induced by radiation therapy during the time of skeletal growth. We have observed exostoses in 28 of 218 children given repeated injections of radioactive bone-seeking 224Ra. The younger the age at irradiation, the higher the incidence of exostoses. Boys are more susceptible than girls. To our knowledge, none of these radiation-induced exostoses have become malignant, although 36 of these children have developed bone sarcomas elsewhere in the skeleton.
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  • 6
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexation in anhydrous methanol of Cu (II) and Zn (II) with diaza-polyoxamacrocyclic ligandsProtonation of five diaza-polyoxamacrocyclic ligands, (L = [2.1], [2.2], [2.1.1.], [2.2.1], [2.2.2]), and their complexing properties towards Cu2+ and Zn2+ cations have been studied in anhydrous methanolic solutions.Potentiometric measurements have been carried out at 25°, using 5 · 10-2MEt4N+ClO4- as support-electrolyte, in order to determine the nature of the species formed upon complexation and their stability constants. The results were confirmed by spectrophotometry, for the cupric complexes of [2.1] and [2.2.2], and the electronic spectra of the different complexes were calculated.Comparison between complexation in aqueous and methanolic solutions have been made: as in water, ML2+ species and sometimes protonated MHL3+ species, with higher stability constants, are present in methanol; but the main difference is the formation of dinuclear complexes M2L4+, between Cu2+ and all ligands except [2.1]. In these complexes the Cu2+ cations cannot be both ‘encaged’ in the ligand cavity because of its small size. The different possible structures are discussed in terms of the stability constants values. The protonation constants values and the existence of the binuclear complexes may indicate a possible conformational change in the complexing ligand on changing the solvent from water to methanol.
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  • 7
    ISSN: 1432-1912
    Keywords: 14C-Toxiferine ; Nicotinic acetylcholine receptor ; Motor endplate ; Endplate potential ; Autoradiography ; Saturation of drug binding sites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. To study the quantitative correlation between the stabilizing effect of toxiferine on the postsynaptic membrane and the number of drug binding sites at the motor endplate, experiments were performed on isolated mouse hemidiaphragms using combined electrophysiological and autoradiographic techniques. 2. The membrane stabilizing effect of 14C-toxiferine was investigated over a wide range of concentrations, in order to obtain not only muscle paralysis but the complete abolition of the endplate response to nerve stimulation. 3. Motor endplate activity was recorded intracellularly. For each concentration of the drug the percentage of endplates reacting to nerve stimulation with action potentials (a.p.), or with subliminal endplate potentials (e.p.p.), or being completely blocked, was determined. The mean amplitude of the e.p.p.'s was also calculated. 4. Reduction of the e.p.p. to an undetectable level required a concentration of 14C-toxiferine about 3 times greater than that which induced complete paralysis. 5. Correlation of these data with autoradiographic measurements demonstrated that decreasing e.p.p. amplitude corresponded to increasing values for the number of drug binding sites per endplate. Saturation was reached by that concentration which completely blocked the postsynaptic sensitivity to ACh. 6. It is concluded that at this concentration all the specific drug binding sites are occupied.
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  • 8
    ISSN: 1432-072X
    Keywords: Methanogenium cariaci ; Methanogenium marisnigri ; Marine methanogenic bacteria ; Ultrastructure ; TaxonomyMethanogenium gen. nov.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new genus of marine methanogenic bacteria and two species within this genus are described.Methanogenium is the proposed genus andMethanogenium cariaci the type species. Cells of the type species are Gram-negative, peritrichously flagellated, irregular cocci with a periodic wall surface pattern. Colonies formed by these bacteria are yellow, circular and umbonate with entire edges. The DNA base composition is 52 mol% guanine plus cytosine. Formate or hydrogen and carbon dioxide serve as substrates for growth. Cells ofMethanogenium marisnigri are of similar shape but smaller diameter thanM. cariaci. The colonies ofM. marisnigri are convex, and the DNA base composition is 61 mol % G+C. Formate or hydrogen and carbon dioxide are growth substrates. Sodium chloride is required for growth of both methanogens.
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