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
    Effects of external electric field on semidilute polymer solutions probed by dynamic light scattering (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 2819-2823 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Dynamic light scattering studies of polystyrene (PS) in tetrahydrofuran (THF) in 1,4-dioxane (DO) and in THF/DO mixed solvent, subject to an external dc field, have been carried out. In THF the rate constant for the decay of the intensity autocorrelation function (IACF) is found to increase with increasing the external applied electric field; in DO, the electric field is found to have only a negligible effect on the IACF; in the mixed solvent it exhibits an intermediate effect, depending on the THF content. A hydrodynamic theory is proposed to account for the observed electric field induced effect in THF. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.473358
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Low-temperature buffer layer for growth of a low-dislocation-density SiGe layer on Si by molecular-beam epitaxy (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 1167-1169 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A method using a low-temperature Si (LT-Si) buffer layer is developed to grow a SiGe epilayer with low density of dislocations on a Si substrate by molecular-beam epitaxy. In this method, a LT-Si layer is used to release the stress of the SiGe layer. The samples have been investigated by x-ray double-crystal diffraction and transmission electron microscopy. The results indicate that the LT-Si is effective to release the stress and suppress threading dislocations. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360899
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Resonant photorefractive AlGaAs/GaAs multiple quantum wells grown by molecular beam epitaxy at low temperature (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 7404-7406 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The resonant photorefractive devices using low temperature AlGaAs/GaAs multiple-quantum-well structures in a parallel field geometry are demonstrated. The samples are semi-insulating as grown. The AsGa-related defects incorporated into the samples during low temperature growth provide the required deep centers. No proton implantation, Cr doping, or annealing is needed for device fabrication. In the photorefractive wave mixing experiment, an output diffraction efficiency higher than 0.84% and a two-wave-mixing gain of more than 3000 cm−1 are obtained under a dc electric field of 15 kV/cm. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.361423
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Neutron scattering studies of the magnetic order in RNi2B2C : The 40th annual conference on magnetism and magnetic materials (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 5857-5859 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Neutron diffraction has been used to investigate the magnetic order of RNi2B2C. For R=Er the system orders antiferromagnetically at TN=6.8 K, and this long range order coexists with superconductivity (Tc=11 K). The magnetic structure is an incommensurate, transversely polarized spin-density-wave state, with the modulation wave vector δ along the a axis and the moments along b. δ has a temperature-independent value of 0.5526 (2π/a), with the structure squaring up at low temperatures. For R=Ho the moments also prefer to reside in the a–b plane, but initially an incommensurate c-axis spiral state forms upon cooling, with TN≈TC≈8 K. This c-axis spiral consists of ferromagnetic sheets of holmium moments in the a–b plane, but with each sheet rotated by ∼163° as one proceeds along the c axis. Small a-axis peaks are also observed above the reentrant superconducting transition over a narrow temperature range, but the c-axis peaks dominate. Just below the reentrant transition at ∼5 K the magnetic system locks-in to a simple commensurate antiferromagnetic structure, which permits superconductivity to be restored. The c-axis spiral, the a-axis component, the commensurate antiferromagnetic structure, and the superconducting phase are all in a delicate balance energetically, and this balance may be easily shifted by subtle changes in composition, magnetic field, and pressure. DyNi2B2C orders antiferromagnetically at TN=11 K, with the same commensurate antiferromagnetic structure as found for the holmium material at low temperature. The existence of superconductivity in some samples of DyNi2B2C is consistent with the antiferromagnetic structure observed. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362150
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Effects of viscoelasticity of bulk polymer solution on the surface modes as probed by laser light scattering (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 6103-6109 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The effects of surface tension, surface dilational modulus, stress relaxation time, and shear stress modulus on the surface laser light scattering (SLLS) spectrum of polymer solutions are investigated. The capillary wave component is significantly affected by both the stress relaxation time and the amplitude of the shear stress modulus. At moderate concentration, before crossing over to the elastic regime, a strong quasielastic component dominates the SLLS spectrum in polymer solution. In the viscoelastic regime, the capillary wave component of the SLLS spectrum is suppressed by the increase of the surface dilational modulus. The decrease of the surface tension gives rise to an effect similar to that caused by increasing the dilational modulus. However, at high polymer concentration in the elastic regime, the dilational modulus has only a negligible effect on the SLLS spectrum, in contrast to the effect of surface tension. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.477237
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Clear-cut experimental observation of the capillary wave to elastic wave crossover in concentrated polymer solutions (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 108 (1998), S. 3827-3834 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A detailed experimental study of the surface laser light scattering (SLLS) spectrum of the polyisobutylene (PIB)/decane solution over a wide range of polymer concentration is carried out. In the dilute solution, the SLLS spectrum is found to be described adequately by a scattering theory from a capillary wave. As the polymer concentration increases, the solution viscoelasticity is found to play an important role in affecting the dynamics of surface waves. By comparing experiment with theory, a clear-cut capillary wave to elastic wave evolution in the PIB/decane solution is found. The nature of the quasielastic peak that appears in the SLLS spectrum of the viscoelastic polymer solution is delineated. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.475771
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Hydrodynamic surface waves in concentrated polymer solutions in the presence of surface adsorption (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 107 (1997), S. 5898-5906 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A theory of light scattering from the polymer solution/air interface that includes the effect of surface adsorption is developed. The polymer solution is assumed to exhibit a linear viscoelastic response. The surface laser light scattering (SLLS) spectrum is calculated from surface hydrodynamic equations appropriate for linear viscoelastic fluids using the method of initial value problems. Numerical calculations are made to investigate the effects of surface tension and dilational modulus on the SLLS spectrum. The results show that the SLLS spectrum from polymer solutions having a high surface tension solvent displays a two-peak structure. The high-frequency peak exhibits more capillary wave character, and diminishes rapidly with decreasing surface tension or increasing dilational modulus as a result of surface adsorption. The two-peak structure is, however, found to be much less pronounced in a solution with a low surface tension solvent. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.474315
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Quasielastic light scattering of polystyrene in diethyl malonate in semidilute concentration (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 105 (1996), S. 6052-6059 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A detailed light scattering study of polystyrene (PS) in diethyl malonate (DEM) semidilute solution has been carried out. DEM is a theta solvent for PS at 32 °C. Dynamic light scattering measurements carried out at temperatures closed to the theta temperature show only a diffusion mode in the intensity autocorrelation function; no slow modes are found in the semidilute PS/DEM solution with concentration up to more than 18 times the overlap concentration. For this system, the mutual diffusion coefficient is found to be mainly determined by the osmotic modulus, with the solution stress modulus making a negligible contribution. A slowing down of the mutual diffusion coefficient as the temperature approaches the critical temperature (at the critical concentration) is observed. These results show that despite considerable chain entanglements existing in the semidilute/concentrated PS/DEM solution, no viscoelastic slow modes are found. These results are not in agreement with the existing literature data for the same system. The absence of the viscoelastic modes is interpreted as due to the fact that PS and DEM are isopycnic and the coupling of concentration fluctuations and the solution stress modulus is negligible for isopycnic polymer solutions, in accordance with a theory recently developed in this laboratory. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.472441
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Characterization of metal-containing carbon films using Raman scattering (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 4520-4525 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Metal-containing carbon (Me-C:H) films were deposited using the electron cyclotron resonance chemical vapor deposition technique in conjunction with a metal screen-grid system. Four sets of Me-C:H films were analyzed using Raman scattering. Two sets were molybdenum-containing carbon (Mo-C:H) films deposited at fixed dc bias (at different CH4/Ar ratios), and at fixed CH4/Ar ratio (at different dc bias). Another two sets of nickel-containing carbon (Ni-C:H) films were deposited at fixed rf power, but at a different CH4/Ar ratio, with and without postgrowth thermal annealing at 200 °C. All films showed the characteristic G and D peaks except for those with high metal content. The D peak is very pronounced in the Ni-C:H films, and both the G and D peaks follow an opposite trend; downshifting and upshifting in wave number, respectively, as the CH4/Ar ratio was increased. In the case of Mo-C:H films deposited at fixed dc bias, both peaks downshifted in wave number, following an increase in the CH4/Ar ratio. The G peak full width at half maximum for both the Ni- and Mo-C:H films increased slightly with an increase in CH4/Ar ratio, consistent with the variation in the relative integrated intensity of the D to G peak (ID/IG). Thermal annealing experiments conducted on the film samples revealed relatively stable characteristics with a minor effect on the film structure. The results showed that the impinging ion energy plays an important role in the structural properties of the Me-C:H films. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1402969
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Comparative study on the effects of ion density and ion energy on diamond-like carbon deposited by electron cyclotron resonance chemical vapor deposition (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 4830-4835 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Diamond-like carbon films were deposited using electron cyclotron resonance (ECR) chemical vapor deposition incorporated with a screen grid under different dc bias voltages to compare the effect of ion density and ion energy on the film properties. Langmuir probe measurements and optical emission spectroscopy were used to characterize the ECR plasma, while the films were characterized using Raman and infrared (IR) spectroscopies, hardness, and optical gap measurements. The plasma measurements showed that the ion density, hydrogen atom density, and CH density decreased monotonously following increase in the dc bias voltage. Raman spectra and optical gap measurements indicate the films became more graphitic with lower content of sp3-hybridized carbon atoms as the dc bias voltage was increased. An increase in hydrogen content was found in films prepared at relatively high dc bias voltage, as indicated by IR measurements. Films deposited at −150 V exhibit maximum hardness. The results show the ion density has a stronger effect on the film deposition rate and hydrogen content, while the ion energy affects the film properties more predominantly by changing the bonding structure. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1359163
    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...