Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Measurement of the H− thermal energy in a volume ion source plasma (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 1212-1219 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The H− negative ion thermal energy measured using the two-laser-pulse photodetachment technique is reported to be in the range from 0.1 to 0.7 eV for various conditions of volume ion source operation (pressure−from 2 to 7 mTorr, discharge current−from 1.5 to 20 A). The hydrogen pressure has a significant effect in lowering the negative ion temperature, while the increase of the discharge current leads to a rise in T−. It is found that T− is a fraction of the electron temperature, Te. This fraction is strongly dependent on the gas pressure. T− scales linearly with the electron temperature and exceeds the highest values predicted by the theory of dissociative attachment. The possible mechanisms for H− ion heating are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.349575
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Observation of fast stochastic ion heating by drift waves (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 3363-3378 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Anomalously fast ion heating has been observed in the Caltech Encore tokamak [Phys. Rev. Lett. 59, 1436 (1987)], with the use of laser-induced fluorescence. This heating was found to be independent of electron temperature, but was well correlated with the presence of large-amplitude drift-Alfvén waves. Evidence is presented that suggests that the heating is stochastic and occurs when the ion displacement due to polarization drift becomes comparable to the perpendicular wavelength, i.e., when k⊥ (mik⊥ φ0/qB2)∼1. Stochastic heating may also be the cause of the anomalously high ion temperatures observed in reversed-field pinches.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859768
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    H− and D− temperature in volume sources : Proceeding of the fourth International Conference on Ion Sources (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 2686-2688 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new technique using laser induced photodetachment has been developed for measuring the negative ion temperature in H− and D− sources. Using this technique, we have investigated the dependence of the negative ion temperature on source parameters such as pressure, discharge current, and electron temperature. Simultaneous measurements of negative ion density, temperature, and extracted current lead to the conclusion that the extracted negative ion current is, at most, equal to the thermal flux.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142823
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    ARC Assembly and Continental Collision in the Neoproterozoic East African Orogen: Implications for the Consolidation of Gondwanaland (1994)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 22 (1994), S. 319-351 
    Details
    ISSN: 0084-6597
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.ea.22.050194.001535
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Peri-implant mucosal aspects of ITI implants supporting overdentures. A five-year longitudinal study. (1994)
    Copenhagen : Munksgaard International Publishers
    Clinical oral implants research 5 (1994), S. 0 
    Details
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Sixty-six ITI implants placed in the mandible of 33 edentulous elderly patients (mean age: 69 years) were observed longitudinally for 5 years. The implants served as overdenture anchorage either by means of a connecting bar or single spherical attachments. During the study period, 2 implants failed (one because of a peri-implant lesion and one because of a fracture) and had to be removed. At the beginning of the study, all implants were osseointegrated and had successfully been in function for 335 months. Oral hygiene practices and the peri-implant mucosal status were assessed according to the criteria of conventional periodontal parameters. Approximately 50% of the implants had been installed into lining mucosa and hence were to surrounded by keratinized mucosa. The peri-implant mucosal tissue was maintained healthy during the whole observation period, and no or only minimal loss of attachment was observed. The probing depths averaged approximately 3 mm. At the end of the study, orthopantomographic radiographs were obtained from all patients to assess the peri-implant bony structures. Small local angular bony defects were detected on 16 implants (22%) in 12 patients. Slightly increased probing depths were observed when angular bony defects were present. Loss of attachment was significantly less frequent when the implants had been placed following a prolonged period of edentulousness (〈5 years). This study demonstrated that advanced age, reduced dexterity of elderly patients and environmental conditions of overdentures do not represent a 1 higher risk for the development of peri-implant lesions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1600-0501.1994.050102.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Nd- and Sr-isotopic compositions of lavas from the northern Mariana and southern Volcano arcs: implications for the origin of island arc melts (1990)
    Springer
    Contributions to mineralogy and petrology 105 (1990), S. 381-392 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Nd- and Sr-isotopic data are reported for lavas from 23 submarine and 3 subaerial volcanoes in the northern Mariana and southern Volcano arcs. Values of εNd range from +2.4 to +9.5 whereas 87Sr/86Sr ranges from 0.70319 to 0.70392; these vary systematically between and sometimes within arc segments. The Nd-and Sr-isotopic compositions fall in the field of ocean island basalt (OIB) and extend along the mantle array. Lavas from the Volcano arc, Mariana Central Island Province and the southern part of the Northern Seamount Province have εNd to +10 and 87Sr/86Sr=0.7032 to 0.7039. These are often slightly displaced toward higher 87Sr/86Sr at similar εNd. In contrast, those lavas from the northern part of the Mariana Northern Seamount Province as far north as Iwo Jima show OIB isotopic characteristics, with εNd and 87Sr/86Sr=0.7035 to 0.7039. Plots of 87Sr/86Sr and εNd versus Ba/La and (La/Yb)n support a model in which melts from the Mariana and Volcano arcs are derived by mixing of OIB-type mantle (or melts therefrom) and a metasomatized MORB-type mantle (or melts therefrom). An alternate interpretation is that anomalous trends on the plots of Nd- and Sr-isotopic composition versus incompatible-element ratios, found in some S-NSP lavas, suggest that the addition of a sedimentary component may be locally superimposed on the two-component mixing of mantle end-members.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00286826
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Gastric dysrhythmias and nausea of pregnancy (1990)
    Springer
    Digestive diseases and sciences 35 (1990), S. 961-968 
    Details
    ISSN: 1573-2568
    Keywords: electrogastrography ; pregnancy ; vomiting ; spectral analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Gastric dysrhythmias have been recorded from patients with a variety of nausea syndromes. The aim of this study was to measure gastric myoelectric activity in women with and without nausea during the first trimester of pregnancy. In 32 pregnant women gastric myoelectric activity was recorded for 30–45 min with cutaneous electrodes that yielded electrogastrograms (EGGs). Frequencies of the EGG waves were analyzed visually and by computer. Subjects rated their nausea at the time of EGG recording on a visual analog scale with 0 representing no nausea and 300 mm severe nausea. Gastric dysrhythmias were found in 26 pregnant subjects: Seventeen had tachygastrias (EGG frequencies of 4–9 cpm),five had 1- to 2-cpm EGG waves, and four had flat-line patterns. Mean nausea scores of the subjects with tachygastrias, 1- to 2-cpm, and flat-line patterns were 64.8±13, 93.4±23, and 77.2±36, respectively. Six pregnant subjects had normal 3-cpm EGG patterns, and their nausea scores averaged 2.8±1.1 (P〈0.05 compared with nausea scores in subjects with tachygastrias, 1- to 2-cpm, and flat-line rhythms). Six subjects with gastric dysrhythmias during pregnancy were restudied after delivery; each of these subjects had normal 3-cpm EGG patterns and none had nausea. Thus, gastric dysrhythmias are objective pathophysiologic events associated with symptoms of nausea reported during the first trimester of pregnancy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01537244
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Synthesis and polymerization of 2-alkylanilines (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 2123-2127 
    Details
    ISSN: 0887-624X
    Keywords: o-alklyaniline ; poly(o-alklyaniline) ; conducting polymer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Alkylanilines with alkyl groups in the range of 4-15 carbon atoms were synthesized via a known method as well as via a more general path which should allow the introduction of a larger variety of substituted alkyl groups into the ortho position of aniline, e.g., alkenyl or OH, NH2, COOH, and phenyl functionality. Polymerization was found to be achievable according to a method previously described for unsubstituted aniline, i.e., chemically with Cu(ClO4)2 · 6H2O in acetonitrile. Intrinsic viscosities of the obtained poly(2-alkylaniline)s lay between 0.10 and 0.26 dL/g (97% H2SO4 at 30°C). The dc conductivity of the HCl salts decreased with increasing length of the alkyl side chains from 1 S/cm (polyaniline) over 3 X 10-4 S/cm [poly(2-butylaniline)] to 1 X 10-6 S/cm poly(tridecylaniline). Further characterization of the polymers were performed by means of UV/VIS/NIR-and-IR spectroscopy, in dilute solutions or as KBr pellets, respectively, and by solubility tests. © 1993 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080310818
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Precambrian basement around Wadi Haifa, Sudan: a new perspective on the evolution of the East Saharan Craton (1994)
    Springer
    International journal of earth sciences 83 (1994), S. 564-577 
    Details
    ISSN: 1437-3262
    Keywords: Precambrian ; Geochronology ; Geochemistry ; Crustal evolution ; Africa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract This paper provides new geochemical and isotopic data on the evolution of the western foreland to the Nubian shield of north-east Africa. There is abundant evidence for early to middle Proterozoic crust west of the River Nile, but this was severely affected by the Pan-African (≈ 500–900 Ma) orogenic cycle. The results are reported of Rb-Sr whole rock and zircon evaporation geochronological studies and whole rock Sm-Nd and feldspar Pb isotopic analyses for four rock units around Wadi Halfa in northernmost Sudan. These results indicate the presence of heterogeneous pre-Pan-African crustal components, preserved in mylonitic gneisses and in conglomerates that unconformably overlie the gneisses. Several episodes of crust formation, inferred from zircon ages, are preserved in the gneisses : 2.6, 2.4, 2.0, 1.7, 1.2 and 0.72 Ga. Nd model ages for the same units are invariably older than the zircon ages, yet still record a predominantly late Archaean and Palaeoproterozoic history, with depleted mantle model ages between 1.3 and 2.8 Ga. The earliest recorded Pan-African magmatic event is about 720 Ma and dates the beginning of collisional deformation. A younger Pan-African volcanic sequence (≈ 650 Ma) has isotopic compositions of Sr and Nd compatible with derivation from late Prote rozoic asthenospheric mantle. A ≈ 530 Ma anorogenic ‘A-type’ granite also has isotopic compositions suggesting derivation from a primitive source. The inferred tectonic evolution began with rifting to form an oceanic re-entrant. This was followed by subduction leading to collision at about 700 Ma, accompanied by post-orogenic rifting at about 650 Ma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194162
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Editorial (1994)
    Springer
    International journal of earth sciences 83 (1994), S. 669-669 
    Details
    ISSN: 1437-3262
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00251066
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...