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  • 1
    Electronic Resource
    Electronic Resource
    Moderatorenbericht Früherkennung des Endometriumcarcinoms (1983)
    Springer
    Archives of gynecology and obstetrics 235 (1983), S. 173-233 
    Details
    ISSN: 1432-0711
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Die Diskussion und das Vorlegen von Erfahrungsberichten im Arbeitskreis hat ergeben, daß eine Früherkennung des Endometriumcarcinoms mit geeigneten morphologischen Methoden grundsätzlich möglich ist. In mehreren Publikatonen wird von einer hohen Erfolgsrate in der Ausbeute des zytologisch aufgearbeiteten intrakavitär gewonnenen Materials gesprochen, die in einzelnen günstig gelagerten Fällen mehr als 90% erreicht. Hier handelt es sich ausschließlich um Testergebnisse vieler Geräte, die unter optimalen Bedingungen erhoben worden sind. Der Arbeitskreis äußerte die Meinung, daß dieses Ergebnis unter ambulanten Bedingungen zum gegenwärtigen Zeitpunkt kaum erreicht werden kann. Die Ursache dafür sind beeinflussende variable Faktoren, die die Auswertbarkeit des intrakavitär gewonnenen Materials einschränken, in manchen Fällen sogar unmöglich machten. Hierzu gehören u. a. Arbeitsgänge wie Materialgewinnung, die Materialverarbeitung oder das Einschätzen von besonderen anatomischen Gegebenheiten. In diesen Zusammenhang gehört auch die möglichst klare und eindeutige Beschreibung und Interpretation des morphologischen Befundes, was wiederum eine zentrale Einrichtung mit geschultem und erfahrenen Personal erfordert. Solange diese Erfordernisse nicht erfüllt sind, werden diese Methoden als Screeningverfahren im Rahmen der Früherkennung des Endometriumcarcinoms noch nicht allgemein praktikabel sein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02428737
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  • 2
    Electronic Resource
    Electronic Resource
    Residual dipolar couplings by 1H dipolar-encoded longitudinal magnetization, double- and triple-quantum nuclear magnetic resonance in cross-linked elastomers (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 111 (1999), S. 402-415 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The measurements of residual dipolar couplings in elastomer system is desirable, because they reflect the hindrance to molecular motions by the cross-linking, topological constraints and the external factors like mechanical stress. Dipolar-encoded longitudinal magnetization nuclear magnetic resonance (NMR) decay curves, double-quantum and triple-quantum NMR buildup intensities for measuring the residual dipolar couplings, and the associated dynamic order parameters are introduced. It is shown that in the short excitation time regime the effective dipolar network is simplified. In the limit of this model based on localized dipolar couplings, the spin response to two-dimensional pulse sequences used to record multiple-quantum (MQ) NMR coherences was evaluated for longitudinal magnetization, double-, and triple-quantum coherences of methylene, and methyl protons in synthetic 1,4-cis-polyisoprene. The dynamic order parameters can be evaluated from this NMR response using a classical scale-invariant polymer model. These dynamic order parameters were measured for a cross-link series of synthetic polyisoprene and correlated with the cross-link density. The decay rates of the Hahn-echo amplitudes reflecting residual dipolar couplings as well as effects of molecular motion are also measured for the same cross-link series. The contribution of molecular motions to the transverse relaxation can be separated from the residual dipolar couplings using a train of magic echoes. The sensitivity of these transverse relaxation rates to the cross-link density is compared to that of residual dipolar couplings. The NMR time scale is shorter for the dipolar-encoded longitudinal magnetization and MQ experiments as compared to transverse relaxation experiments leading to an increased sensitivity to cross-link density of the former approaches. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.479291
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  • 3
    Electronic Resource
    Electronic Resource
    Magnetic force microscopy of domain wall fine structures in iron films (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 8578-8583 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: This work investigated the micromagnetic structure of single crystal iron films by means of magnetic force microscopy (MFM) and Kerr microscopy. The investigated samples were epitaxially grown Fe films on a GaAs substrate. The film thickness varied between 30 and 500 nm. With the Kerr microscope it was possible to localize efficiently the domain walls in iron films. These walls were subsequently imaged by MFM with a high resolution. The MFM was used to observe the fine structure of a Bloch wall. Experimental results were compared with the calculated MFM response that was based on a two-dimensional, micromagnetic model describing the magnetic structure of an asymmetric Bloch wall. Both theory and experiment demonstrated the influence of the stray field of the tip on the wall structure. We could observe symmetric Néel walls and cross tie walls in a 30 nm iron film after reducing the sensitivity of the MFM tip. In order to achieve this state the tip was demagnetized by an external field. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362539
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  • 4
    Electronic Resource
    Electronic Resource
    Investigation of 90° coupling in Fe/Ag/Fe structures: "Loose spins'' and fluctuation mechanism (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 6432-6438 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Results are outlined of experimental work concerning Slonczewski's theories explaining 90° coupling: "loose spin'' theory and thickness-fluctuation mechanism. The loose spin theory suggests that 90° coupling originates from paramagnetic impurities in the interlayer of an exchange-coupled layered structure. The influence of these paramagnetic impurities on the magnetic exchange coupling was studied using the wedge technique. High-quality single-crystalline Fe/Ag/Fe samples were prepared in UHV and each sample consisted of two wedges: one wedge with additional Fe deliberately inserted during growth into the Ag interlayer and one wedge with a pure Fe/Ag/Fe structure. The detailed analysis of magneto-optic hysteresis loops revealed quantitatively the bilinearly and the 90° coupling strength. As predicted by loose spin theory additional Fe in the Ag spacer lead to a strong temperature dependence of the 90° coupling. According to the theory an increase of 90° coupling strength proportional to impurity concentration was detected while the strength of bilinear coupling decreased. For the pure Fe/Ag/Fe structure, a linear increase of the 90° coupling strength with decreasing temperature was observed. This result can be explained within the fluctuation mechanism which creates 90° coupling through a combination of interface roughness and intralayer ferromagnetic exchange. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359117
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  • 5
    Electronic Resource
    Electronic Resource
    A 14.6-GHz ECR ion source for atomic physics and materials research with highly charged slow ionsa) (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 3078-3083 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A 14.6-GHz electron cyclotron resonance ion source has been designed and will be installed at the TU Dresden. Contrary to other ECR sources some features are foreseen for atomic physics experiments to study the source plasma. Beside the description of source construction and computer-aided source control first physical experiments on the source are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142610
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  • 6
    Electronic Resource
    Electronic Resource
    Analysis of failure mechanisms in electrically stressed Au nanowires (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 1280-1286 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An analysis of polycrystalline Au thin film interconnects of widths ranging from 850 to 25 nm, and lengths ranging from 1.0 μm to 20 nm which have been electrically stressed to the point of failure is presented. For the longer wires (widths 60–850 nm), the failure current density is typically found to be 1012 A m−2, essentially independent of the wire width, and then rapidly approaching zero for thinner wires. For the wider wires, failure occurs at the end towards the negative electrode; for narrow wires, failure tends to occur towards the center of the wire, as observed using scanning electron microscopy and atomic force microscopy. The mean time to failure for fixed current density is seen to decrease with decreasing wire width. The failure current density for a given wire width increases as the length decreases. An analysis of the temperature profile based on calculations of a simple model is presented which shows that this width-dependent behavior of narrow lines is not anticipated from the assumption of a homogeneous line subject to thermally-assisted electromigration alone. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.370882
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  • 7
    Electronic Resource
    Electronic Resource
    Stability of magnetic vortices in flat submicron permalloy cylinders (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 92 (2002), S. 1466-1472 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated the magnetic properties of flat permalloy cylinders by Lorentz transmission electron microscopy and micromagnetic simulations. The magnetization patterns during in situ magnetizing experiments have been imaged and they revealed that the magnetization reversal of the cylindrically shaped dots investigated is determined by the formation and annihilation of magnetic vortices. Furthermore, the experiments and micromagnetic simulations showed a dependence of the vortex annihilation field not only on the aspect ratio but also on the absolute thickness of the cylinders. The diameter of the cylindrical dots was varied between 150 and 1000 nm, and the thicknesses were 3, 5.5, 8.3, 15, and 20 nm, respectively. The formation of inhomogeneous magnetization patterns prior to vortex evolution was observed and by a comparison of the experimental to simulated Fresnel images these patterns can be identified as S- and C-like states. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1490623
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  • 8
    Electronic Resource
    Electronic Resource
    Magnetization loops of submicron ferromagnetic permalloy dot arrays (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 4539-4543 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Polycrystalline Permalloy films were deposited onto silicon substrates by rf sputtering. Arrays of cylindrical dots with diameter d between 150 and 550 nm were patterned by optical holographic lithography. The dots were arranged on a square lattice with period p, ranging from 310 to 1030 nm. The height h of dots, given by the thickness of the permalloy films, ranged between 10 and 80 nm. The shape of the magnetization loops of the dot arrays depends strongly on the aspect ratio r=d/h. The in-plane saturation field is given by the intrinsic demagnetization field of single, isolated dots. The dipolar interaction between the dots is negligible. For cylinders with elliptical base plane, the magnetization loop depends on the field direction. The measured magnetization loops of the arrays are the superposition of the magnetization loops of the single dots without dipolar interaction. A model of magnetization reversal in applied fields is given. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371399
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  • 9
    Electronic Resource
    Electronic Resource
    Optical characterization of selectively intermixed GaAs/GaAlAs quantum wires by Ga+ masked implantation (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 1444-1450 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Quantum wires were fabricated by selective intermixing of a GaAs/GaAlAs quantum well through masked Ga+ implantation and rapid thermal annealing. The evolution of the luminescence spectra of the wires with the width of the implantation masks, enabled us to characterize the lateral selectivity of our process as well as the degree of one-dimensional confinement. The lateral extent of the intermixing was estimated at 20 nm giving rise to an important penetration of aluminum into the wires. From numerical simulations of the spatial distribution of implantation-induced damage, it was concluded that some lateral diffusion of the defects occurred during annealing. However it has been possible to assess the confinement energies to be around 4 meV. The linewidth of the wires' emission turned out to increase with decreasing mask size, indicating the presence of some fluctuations of the confining potential along the wires. The roughness of the lateral definition of the wires was evaluated at 20 nm, of the same order of magnitude as the dimension of the intermixed region under the mask. Under these conditions optical excitation spectroscopy failed to detect the different one-dimensional subbands. Finally the potentialities of this method of fabrication of quantum wires are inspected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.349555
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  • 10
    Electronic Resource
    Electronic Resource
    Damage generation and annealing in Ga+ implanted GaAs/(Ga,Al)As quantum wells (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 4833-4842 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The damage generation and its annealing behavior in GaAs/(Ga,Al)As quantum wells after Ga+ implantation at room temperature is investigated by transmission electron microscopy. Its relations with the disordering of the layered structures is explored by low temperature photoluminescence spectroscopy. We find that at low doses the intermixing is activated during annealing through the diffusion of point defects, while at high doses the disordering is produced by cascade mixing. A strong segregation of the defects in the GaAs layers is observed. During implantation of a GaAs/Ga0.65Al0.35As single quantum well, the GaAs quantum-well layer accumulates damage more rapidly than the Ga0.65Al0.35As barriers. At high dose this leads to a differential amorphization of the two compounds. Using the critical damage energy density model, the amorphization thresholds of GaAs and Ga0.65Al0.35As are estimated around 26 eV/molecule and 960 eV/molecule, respectively, in our conditions of implantation. The influence of barriers in AlAs is studied. AlAs is more resistant to amorphization than Ga0.65Al0.35As and delays the amorphization of the GaAs quantum-well layer. This effect is attributed to the in situ recombination of point defects during irradiation in AlAs material as well as to some intermixing of the layers. After annealing it appears that defects can easily diffuse in Al rich materials but are trapped in GaAs. It is concluded that the ability of AlAs to prevent damage accumulation in GaAs quantum wells and to drain off the defects during annealing can be exploited for device applications. The general trends for an optimized GaAs/GaAlAs quantum well dedicated to mixing applications such as the fabrication of quantum-well wires by masked implantation is finally proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350626
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