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  • 1
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    The @journal of organic chemistry 30 (1965), S. 310-312 
    ISSN: 1520-6904
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 2044-2047 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Scanning tunneling microscopy has been applied to obtain atomically resolved images of polydiacetylene on graphite and to observe hydrogen bonding between polymers directly. Polydiacetylenes have a pseudo-one-dimensional conjugated pi-electron system which gives rise to nonlinear optical behavior of both fundamental and practical significance. Under low surface coverage, the images show a single polymer of CH3(CH2)11—C≡C—C≡C—(CH2)8—COOH. At high coverage, the images show a well-ordered monolayer of polymers with the nonpolar side groups pointing toward the hydrophobic graphite surface. The spatial electron distribution indicates substantial hydrogen bonding between polymers in the plane containing the polar side groups.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    350 Main Street , Malden , MA 02148 , USA , and 9600 Garsington Road , Oxford OX4 2DQ , UK . : Blackwell Publishing, Inc.
    Risk analysis 23 (2003), S. 0 
    ISSN: 1539-6924
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Energietechnik
    Notizen: The 1991 eruption of Mount Pinatubo in the Philippines is considered one of the most violent and destructive volcanic activities in the 20th century. Lahar is the Indonesian term for volcanic ash, and lahar flows resulting from the massive amount of volcanic materials deposited on the mountain's slope posed continued post-eruption threats to the surrounding areas, destroying lives, homes, agricultural products, and infrastructures. Risks of lahar flows were identified immediately after the eruption, with scientific data provided by the Philippine Institute of Volcanology, the U.S. Geological Survey, and other research institutions. However, competing political, economic, and social agendas subordinated the importance of scientific information to policy making. Using systemic risk analysis and management, this article addresses the issues of multiple objectives and the effective integration of scientific techniques into the decision-making process. It provides a modeling framework for identifying, prioritizing, and evaluating policies for managing risk. The major considerations are: (1) applying a holistic approach to risk analysis through hierarchical holographic modeling, (2) applying statistical methods to gain insight into the problem of uncertainty in risk assessment, (3) using multiobjective trade-off analysis to address the issue of multiple decisionmakers and stakeholders in the decision-making process, (4) using the conditional expected value of extreme events to complement and supplement the expected value in quantifying risk, and (5) assessing the impacts of multistage decisions. Numerical examples based on ex post data are formulated to illustrate applications to various problems. The resulting framework from this study can serve as a general baseline model for assessing and managing risks of natural disasters, which the Philippines' lead agency—the National Disaster Coordinating Council (NDCC)—and other related organizations can use for their decision-making processes.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 57 (1990), S. 2847-2849 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A new model is proposed in which a photon of energy E=hf is absorbed by a superconducting film to create a pair of equal and opposite fluxons (or vortices), each with quantized flux Φ0=h/2e. An applied current sweeps these fluxons to opposite edges of the film, causing a voltage pulse with time-integrated magnitude Φ0, and leading to a time-averaged voltage responsivity Rv = Φ0/E = 1/(2ef). This is directly analogous to photoconductive detection in a semiconductor via creation of electron-hole pairs. Data on an ultrathin granular NbN film are presented which indicate a responsivity of 6000 V/W in red light, in agreement with the model. This is promising for the development of a sensitive, high-speed infrared detector using thin films of either low or high Tc superconductors.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 56 (1990), S. 1537-1539 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Recent studies have shown that, after a preparative photowashing step, water, oxygen, and light must all be present in order to produce Fermi level unpinning of gallium arsenide surfaces. The in situ photoluminescence (PL) investigations in an optical flow cell reported here confirm this finding and show that the unpinning and subsequent repinning processes speed up with an increase in oxygen concentration in the water during photoluminescence measurements. When the water is saturated with hydrogen the surface unpins, although more slowly than if the water were saturated with oxygen, air, or nitrogen. In addition the surface remains unpinned for longer periods. The PL transient response data suggest that hydrogen is an active participant in surface photochemical reactions. A conceptual model is advanced that is consistent with the experimental data on pinning/unpinning processes on the GaAs surface.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 51 (1987), S. 2046-2047 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: It is demonstrated here that granular films of Y-Ba-Cu-O may serve as optical detectors, operating at wavelengths from the visible to the far infrared, at temperatures well above that of liquid helium. Preliminary measurements using a blackbody source show that an upper bound of the minimum detectable power is 1 μW. The response time as determined by a pulsed far-infrared source is of the order 20 ns. Methods to improve the sensitivity will be discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 172-175 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Laminar-flow polishing is a noncontact polishing technique capable of producing a highly polished surface with no subsurface mechanical damage. The method utilizes the hydrodynamic condition of laminar flow to provide the transport mechanisms responsible for the removal of the GaAs surface. The method is well suited to the preparation of semiconductor wafers for experiments where high-quality damage-free substrates are required. In addition, the ease of controlling the polishing conditions makes this method a useful technique in production where a high throughput of wafers with uniform and damage-free surfaces are essential.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 56 (1985), S. 2290-2294 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Auger analysis combined with ion etching in the scanning Auger microprobe (SAM) provides "three-dimensional'' composition information not readily obtainable from other analytical methods. As this technique is being applied to the analysis of microelectronic devices with increasingly smaller dimensions, two major limitations became evident: (1) features of interest in microelectronic circuits are often comparable in size to the beam diameter of commercial Auger microprobes and (2) the electron beam tends to drift about on the specimen surface because of mechanical instability and differential thermal expansion. We describe a technique that will reduce the error and uncertainty caused by beam instability. In our technique, the analyzing beam is scanned repetitively across the feature to be profiled and the Auger signal is synchronously detected at the scan frequency. This position modulation technique allows a tradeoff between depth resolution and sensitivity on the one hand and drift in spatial position of the analyzing electron beam. Position modulation is particularly suited to the analysis of microelectronic devices (e.g., microwave field effect transistors), where the dimensions of features of interest are comparable to the electron beam diameter.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 2198-2201 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Subsurface damage in polished GaAs wafers has been identified by electron microscopy and other surface analytical techniques. The presence of subsurface damage can adversely affect the performance and reliability of a device fabricated on such substrates. In this article, we introduce a method for determining the degree of subsurface damage as a function of depth. Interferometry is used to measure the rate at which substrate material is being etched from the sample. Measuring the etch rate as a function of depth reveals the profile of subsurface damage in the sample. We describe the methodology and present our findings on GaAs wafers that have been subjected to surface damage. Samples obtained from different wafer manufacturers were investigated.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Journal of the American Chemical Society 97 (1975), S. 669-670 
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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