ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
    Study of chemical gelation dynamics of acrylamide in water by real-time pulsed nuclear magnetic resonance measurement (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 3363-3372 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Chemical gelation process of acrylamide monomers in water has been studied by a real-time pulsed nuclear magnetic resonance (NMR) measurement. The temporal change of molecular mobility has been detected by a real-time observation of the spin–spin relaxation time T2. The influence of the concentration of crosslinker and acrylamide on gelation dynamics has been studied, and it becomes clear that these factors have strong effects on the gelation dynamics. The effects of linear polymerization and network formation on the motional state of water have been studied. The formation of three-dimensional cages drastically reduces the mobility of water. In low acrylamide concentration, the results of NMR measurement mainly reflect the state of water. In high acrylamide concentration, on the other hand, they reflect both polymer network and water, and furthermore, in high crosslinker concentration the spatial heterogeneity of gels is observed. In this paper, we demonstrate that a real-time NMR measurement is a useful tool for a direct observation of the temporal change of molecular mobility during polymerization and gelation process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454945
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Dynamics of ferroelectric phase transition in vinylidene fluoride/trifluoroethylene (VF2/F3E) copolymers. I. Acoustic study (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 6730-6739 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We report the behavior of ultrasonic absorption and velocity in the ferroelectric copolymers of vinylidene fluoride (VF2) and trifluoroethylene (F3E) near the Curie point. The ferroelectric transition of VF2/F3E is strictly of the first order, however, it has the second-order character especially in the copolymers with low VF2 content. A large critical absorption due to cooperative fluctuation has been observed near the Curie point. From the temperature dependence of the critical absorption, we have found that the critical anomaly of the absorption is weak and the specific heat has logarithmic divergence at the Curie point if we ignore the effect of the distribution of the Curie point which may come from a distribution of lamellar thickness. This weak critical anomaly can be ascribed to the long-range nature of the bare interaction between dipoles due to connectivity of polymer chain or the electric dipolar interaction, the randomness of the interaction due to random copolymerization, and/or the dimensionality of the order parameter. The rotation of dipole is always accompanied by cooperative conformational change of the backbone, which is unique to a polymer chain. We have also found that a type of the dominant interaction between acoustic phonon and the order parameter depends on VF2 content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456292
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Dynamics of ferroelectric phase transition in vinylidene fluoride/trifluoroethylene (VF2/F3E) copolymers. II. Proton nuclear magnetic resonance study (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 6740-6748 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Here we study the ferroelectric phase transition of a random copolymer of vinylidene fluoride (VF2) and trifluoroethylene (F3E), VF2/F3E(52/48), by 1H-pulsed nuclear magnetic resonance (NMR). Spin–spin relaxation time T2, spin–lattice relaxation time T1, and T1 in the rotating frame T1 ρ show the anomaly reflecting the phase transition. We demonstrate that the motional state in the crystalline and amorphous region is not so different. From the direct fitting of the Kubo–Tomita relation to a free induction decay, we have succeeded in obtaining the correlation time of the fluctuating local field and the second moment of the rigid lattice separately. The critical slowing down of the order-parameter fluctuation is observed through the temperature dependence of the correlation time. The anomaly of T1 near the Curie point has been found to be weak. This weak divergence of T−11 is consistent with our results on acoustic measurements. The weak anomaly can be ascribed to (1) the long-range nature of the bare interaction between dipoles which may come from the connectivity of a polymer chain (a cooperative conformational change over at least three bonds) or the dipolar long-range interaction, (2) the randomness due to random copolymerization, and/or (3) the dimensionality of the order parameter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456293
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Real-time pulsed nuclear magnetic resonance measurement system for the study of nonequilibrium phenomena in polymers (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 60 (1986), S. 1306-1309 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A real-time pulsed nuclear magnetic resonance measurement system controlled by a microcomputer has been constructed. The real-time measurements of the spin-spin relaxation time T2, the spin-lattice relaxation time in the rotating frame T1ρ, and the spin-lattice relaxation time T1 become possible by the use of this system. It is applicable to the studies of nonequilibrium phenomena in polymers such as crystallization, phase separation, gelation, polymerization, etc. It is also applicable to wider fields such as biological reaction and chemical reaction. The application of this system to polymer crystallization is presented as an example.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.337301
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Digital image analysis of droplet patterns in polymer systems: Point pattern (1989)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 65 (1989), S. 4480-4495 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: New techniques of digital image analysis which are especially suitable for analyzing particle-distribution patterns are presented. Statistical mathematical methods are applied to the quantitative analysis of a spatial distribution of points in polymer systems. The techniques are useful for studying the spatial patterns of particles or droplets which are commonly observed in nucleation-growth-type phase separation and late-stage spinodal decomposition in polymer mixtures, crystallization process, microphase separation in block copolymers, incompatible polymer alloys, and composite materials, etc. We can divide point patterns into three typical point patterns: the Poisson pattern, the clustered pattern, and the regular pattern. The kind and strength of interaction or force between points can be determined from spatial point-distribution patterns. The point-pattern analysis has been applied to phase-separated structures of a polymer mixture, and it has been revealed that the pattern belongs to the regular pattern. The appearance of the regular pattern is probably a result of the Brownian coalescence mechanism for the droplet growth and it might also be due to a long-range interaction among droplets through diffusion field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.343266
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Application of digital image analysis to pattern formation in polymer systems (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 3627-3643 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Digital image analysis (DIA) is applied to extract various types of physical information from an image of high-order structures in polymer systems observed under an optical microscope. DIA can be applied to analyze the pattern formation phenomena in general. Various numerical operations in real and wave-number space make it possible to extract physical information unobtainable by other methods, such as the use of light scattering. The possibility of valuable operations in DIA are presented with examples. The technique itself is useful not only in polymer systems but also in various fields such as studies of liquid crystals, biological systems, metals, and pattern formation in solution or chemical reaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.336795
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Real-time measurement of crystallization process of polymers by pulsed nuclear magnetic resonance (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 1488-1492 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Real-time measurement of the crystallization process of polymers [poly(ε-caprolactone) and its blend with poly(vinyl methyl ether) and polystyrene] by pulsed nuclear magnetic resonance has been made. The measurements on both the spin-spin relaxation time T2 and the spin-lattice relaxation time in the rotating frame T@B|1 ρ have been performed for the first time. From the data, we can obtain information on the temporal change of the crystallinity as well as the change of the mobility in each phase. Furthermore, the temporal change of the intermediate phase corresponding to the interface between crystalline and amorphous part has been successfully detected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.336504
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Application of digital image analysis to the study of high-order structure of polymers (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 653-655 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A digital image analysis (DIA) technique has been applied directly to the study of the high-order structure of polymers probably for the first time. Using this method, various types of physical information can be obtained in real and wave-number (k) space. Included in this DIA method are operations such as two-dimensional Fourier transformation, cross sectional profiles along various curves, the size and shape distribution of droplets, etc. This technique is widely applicable to any image obtained by optical microscopy, electron microscopy, ordinary photography, etc. In this communication, we apply the DIA method to the study of the pattern formation in polymers, namely the structure of spherulite and phase separation in polymer blends.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.336627
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    A new light scattering technique for a wide-band ripplon spectroscopy at the MHz region (1991)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 62 (1991), S. 1192-1195 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new light scattering system was developed to investigate the propagation of liquid surface waves over a wide wave-number range 4×104–3×106 m−1 (or 10 kHz–6 MHz in frequency). Thermal fluctuation of liquid surface displacement excites a surface tension wave called a "ripplon'' whose behavior yields information on the dynamics of the liquid surface. The transmission diffraction method and some optical and electrical improvements are successfully applied to the light scattering system and the upper limit of the frequency measured was extended about two orders higher than the conventional one. The wave-number dependence of the ripplon frequency and damping constant was measured for several kinds of liquids and the results agreed well with the classical hydrodynamic theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141999
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    New instrument for measuring complex adiabatic compressibility and adiabatic pressure-induced temperature variation of liquids in the frequency range from 0.5 Hz to 2 kHz (1986)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 57 (1986), S. 2593-2598 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new instrument is presented for measuring complex adiabatic compressibility and adiabatic pressure-induced temperature variation (∂T/∂P)S of liquids in the low-frequency range from 0.5 Hz to 2 kHz. The relative accuracy of the measurement is of the order of 10−3–10−4. The velocity and absorption coefficient of sound in the low-frequency range give us information on slow relaxational phenomena. (∂T/∂P)S, which is directly related to the ratio of thermal expansion coefficient to specific heat, can be measured accurately by ac method. The measurement of these quantities provides us with new information on thermodynamic or low-frequency relaxational behavior of liquids, including critical liquids, liquid crystals near their phase transitions, and biological materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1139064
    Location Call Number Expected 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...