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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Blackwell Science Ltd/Inc.
    Contact dermatitis 50 (2004), S. 0 
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Germall 115 and Germall II are well known cosmetic preservatives, widely used as such since the early 1970’s and 1980’s, respectively. This investigation reveals that they have mistakenly been regarded as pure chemical entities with specific structures by the majority of the chemical society. In fact Germall 115 and Germall II both consist of complex mixtures of numerous and fast degradable allantoin-formaldehyde condensation products and may not even contain the conventionally assigned chemical structures of imidazolidinyl urea (Germall 115) and diazolidinyl urea (Germall II). Equilibrium between different structures may be formed in different cosmetic formulations/test materials. This may have led to the discrepancies in the literature: Are the Germalls themselves sensitizers or are the allergic reactions caused by formaldehyde release? The identification and structure assignment of (4-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-urea (HU) will be presented, as it is the major and chemically stable degradation product of both Diazolidinyl urea and Imidazolidinyl urea. A guinea pig maximization test has been performed to determine the potential of HU to induce delayed contact hypersensibility in guinea pigs. Separate chemically stable TRUE Test patches containing the mixtures have shown clinical efficacy.
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 2438-2441 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A simple and economical method to determine the overall purity of inert gases such as Ar and He is described which uses the filament of commercial light bulbs. The lifetime of the incandescent filament is sensitive to gas impurities such as O2, H2O, and some hydrocarbons, but insensitive to N2 and, to first order, to the applied voltage. The relationship between the filament lifetime, τ, and the O2 and H2O concentrations was carefully calibrated. The relationship follows a power law: τ=AC−γ, where A and γ are positive constants depending on the impurity type. For mixtures of O2 and H2O, a simple superposition rule for the overall lifetime, τoverall, as 1/τoverall = 1/τO2 + 1/τH2O, applies. A mechanism for the concentration dependence of the filament lifetime is proposed in which the creep of the filament is enhanced by the impurity solutes in the filament. With a lifetime spanning from a few seconds to a few days, the filament acts as a simple gauge for the determination of impurity concentrations in an inert atmosphere. As an example, for O2, the measurable concentrations vary from 105 ppm to 10−2 ppm. © 1997 American Institute of Physics.
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 5019-5031 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new rheometer is described. It consists of a transducer unit supplied with an electric impedance analyzing unit. The transducer unit converts a mechanical impedance into an electrical impedance by the piezoelectric effect. A detailed quantitative analysis of the interaction between the sample and the transducer is given. The real and imaginary parts of the shear modulus of a viscoelastic sample can be found in the frequency range of 1 mHz–50 kHz, modulus range of 0.1 MPa–10 GPa, and the temperature range of 150–300 K. The sample volume is 0.3 cm3 and the strain amplitude is exceedingly small. The small size of the transducer allows for good temperature control and equilibration. It has a simple construction based on inexpensive components. Results on the supercooled liquid 2-metyl-2,4-pentandiol at the glass transition obtained by the method are included. © 1995 American Institute of Physics.
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  • 4
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A review of the diagnostics used at Sandia National Laboratories to measure the parameters of intense lithium ion-beam hohlraum target experiments on Particle Beam Fusion Accelerator II will be presented. This diagnostic package contains an extensive suite of x-ray spectral and imaging diagnostics that enable measurements of target temperature and x-ray output. The x-ray diagnostics include time-integrated and time-resolved pinhole cameras, energy-resolved one-dimensional streaked imaging diagnostics, time-integrated and time-resolved grazing incidence spectrographs, a transmission grating spectrograph, an elliptical crystal spectrograph, a bolometer array, an 11- element x-ray diode array, and an 11-element PIN diode detector array. The incident Li beam symmetry and an estimate of incident Li beam power density can be measured from ion beam-induced characteristic x-ray line emission and neutron emission. © 1995 American Institute of Physics.
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  • 5
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The Holifield Radioactive Ion Beam Facility now under construction at the Oak Ridge National Laboratory will use the 25 MV tandem accelerator for the acceleration of radioactive ion beams to energies appropriate for research in nuclear physics; negative ion beams are, therefore, required for injection into the tandem accelerator. Because charge exchange is an efficient means for converting initially positive ion beams to negative ion beams, both positive and negative ion sources are viable options for use at the facility. The choice of the type of ion source will depend on the overall efficiency for generating the radioactive species of interest. Although direct-extraction negative ion sources are clearly desirable, the ion formation efficiencies are often too low for practical consideration; for this situation, positive ion sources, in combination with charge exchange, are the logical choice. The high-temperature version of the CERN-ISOLDE positive ion source has been selected and a modified version of the source designed and fabricated for initial use at the facility because of its low emittance, relatively high ionization efficiencies, and species versatility, and because it has been engineered for remote installation, removal, and servicing as required for safe handling in a high-radiation-level ISOL facility. The source will be primarily used to generate ion beams from elements with intermediate to low electron affinities. Prototype plasma-sputter negative ion sources and negative surface-ionization sources are under design consideration for generating radioactive ion beams from high-electron-affinity elements. The design features of these sources and expected efficiencies and beam qualities (emittances) will be described in this report.
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  • 6
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 3310-3312 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A technique for measuring the instantaneous deformation rate of hydrogel microstructures is introduced. In developing this technique, we have adapted microscopic particle image velocimetry, a method for measuring velocity fields in microfluidic devices. Small fluorescent seed particles are incorporated into the hydrogel microstructure, and as the structure swells or contracts, the displacement of the seed particles over some small time Δt is measured using a cross-correlation technique. By providing local deformation rate data in hydrogel microstructures, this technique will allow for optimization of device designs as well as providing a means for determining the validity of hydrogel expansion models. © 2000 American Institute of Physics.
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  • 7
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 1176-1178 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Anisotropic bulk Sm2(Fe,M)17Nx magnets were prepared by rotation aligning easy plane Sm2(Fe,M)17 powders followed by sintering and nitriding. Vanadium substitution for iron can help the c-axis alignment compared to the binary Sm2Fe17 compound. Magnets with an energy product of 15 MG Oe and an intrinsic coercivity of 7 kOe were obtained on a single phase Sm2Fe16.15V0.85Nx compound with a density of 91% of theoretical density. © 1997 American Institute of Physics.
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  • 8
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 60 (1992), S. 2054-2056 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A novel guided-wave electroabsorption modulator, based on separate confinement of the optical modes and the applied electric field, is described. When demonstrated for 633 nm light using AlGaAs waveguide technology, the concept provides low insertion loss and extinction ratios as great as 100:1 (20 dB) while operating at less than 10 V. Other advantages include polarization insensitivity and low capacitance.
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  • 9
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The extent of relaxation and orientation of linearly graded InxAl1-xAs (x=0.05–0.25) buffers grown on GaAs were examined using a novel x-ray diffraction reciprocal-space mapping technique (kmap). Samples were grown at temperatures ranging from 370 to 550 °C. The fractional relaxation of the buffers grown between 470 and 550 °C was essentially identical (77%) and symmetric in orthogonal 〈110〉 directions. These buffers are believed to be in equilibrium indicating that the incomplete relaxation is not a kinetic effect. The extent of relaxation was less than that expected for equilibrium relaxation in the absence of dislocation–dislocation interactions indicating that such interactions must be considered to accurately predict the extent of relaxation. The saturation of the relaxation as a function of temperature indicates that at the grading rate used (8% In/μm or 0.69% strain/μm), we are not working in a growth regime where the relaxation is nucleation limited. In addition, all the buffers are slightly tilted with respect to the GaAs substrate about [11¯0] toward the [110] direction suggesting either a bias in the dislocation types in the boule-grown GaAs, or a bias in the way in which α and β dislocations interact with unintentional substrate miscuts. © 1996 American Institute of Physics.
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  • 10
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The structural and magnetotransport properties have been studied in (Ni81Fe19,Ni80Co20)/Ag granular alloy films synthesized by the annealing of sputtered multilayers containing ultrathin magnetic layers. The magnetic concentration, particle size, and morphology of the precipitates can be controlled by adjusting the magnetic layer thickness during the deposition process. Magnetoresistance as large as 30% was found at 4.2 K with a rather small saturation field (〈2 kOe), leading to relatively high field sensitivity. Magnetoresistance and saturation field in these alloy films essentially depend on the magnetic precipitate size, concentration, and annealing temperature. The temperature dependence of magnetization and magnetoresistance was also studied, and the correlations among the microstructure, magnetotransport, and magnetic properties are discussed.
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