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
    Preparation of homogeneous Cu(InGa)Se2 films by selenization of metal precursors in H2Se atmosphere (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 3978-3980 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Homogeneous single phase Cu(InGa)Se2 films with Ga/(In+Ga)=0.25–0.75 were formed by reacting Cu–Ga–In precursor films in H2Se followed by an anneal in Ar. X-ray diffraction and Auger analysis show that the metal precursors reacted only in H2Se were multiphase films having a layered CuInSe2/CuGaSe2 structure. Solar cells made with the multiphase films have properties similar to CuInSe2 devices. Cells made with the annealed single phase films behave like Cu(InGa)Se2 devices with the band gap expected for the precursor composition. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.114424
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Structure and property development in poly(p-phenylene terephthalamide) during heat treatment under tension (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 1-14 
    Details
    ISSN: 0887-6266
    Keywords: poly (p-phenylene terepthalamide) ; Kevlar® ; heat treatment ; structure development ; mechanical properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The evolution of several structural characteristics during isothermal heat treatment of poly(p-phenylene terephthalamide) was studied. In this work, heat treatment was interrupted after different treatment times, with the specimens immediately quenched to room temperature. These specimens were then characterized by tensile testing, wide- and small-angle x-ray scattering, and optical microscopy. Structural parameters obtained from these measurements relate to crystal perfection (via the paracrystalline axial distortion parameter), axial crystallite size, transverse crystallite size, degree of chain misorientation, and degree of pleating. Structural and mechanical parameters were then plotted against heat-treatment time to obtain kinetic isotherms for each parameter. The kinetics of the removal of chain misorientation parallels that of tensile modulus increase under all conditions. Of the other structural parameters, only the kinetics of pleat removal mimics that of modulus change, indicating that pleat removal is the effective cause of increased chain alignment and thereby of increased axial stiffness. ©1995 John Wiley & Sons, Inc.
    Additional Material: 27 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1995.090330101
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Rapid mechanical deformation of poly(ethylene terephthalate) fibers at temperatures above the glass transition (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 125-133 
    Details
    ISSN: 0887-6266
    Keywords: mechanical deformation ; PET ; high-temperature deformation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The mechanical properties of poly(ethylene terephthalate) (PET) fibers at temperatures above the glass transition are investigated by means of a specially constructed device. Measurements of the deformation rate and of the “dynamic” stress-strain curves of the fibers are performed in nearly isothermal regime (after initial rapid heating) in a temperature interval 100-200°C. The results reported in the present work demonstrate that the high-temperature mechanical characteristics of rapidly crystallizing polymers can be deduced to a satisfactory precision, while keeping the crystallinity development at low level. Our investigations indicate that if the high-temperature deformation is sufficiently fast, the polymer behavior is similar to the deformation at sub-Tg temperatures. Based on this similarity, a qualitative model of the deformation in the high-temperature region is proposed. The proposed model is fundamentally equivalent to the models describing mechanical deformation of glassy polymers at temperatures below the glass transition. ©1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1995.090330113
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    AFM study of morphological development during the melt-crystallization of poly(ethylene oxide) (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 2311-2325 
    Details
    ISSN: 0887-6266
    Keywords: poly(ethylene oxide) ; crystallization ; AFM ; spherulites ; crystal growth ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The atomic force microscope (AFM) has been used to investigate morphological development during the crystallization of poly(ethylene oxide) (PEO) from the melt. PEOs with molecular weights of 1 × 105 and 7 × 106 were used. Height and amplitude images were recorded, using the tapping mode. For both polymers, the mode of spherulite development varied with the velocity of the growth front. For slow growth velocities, the growth of the crystallites was linear, with growth initially occurring by single lamellae, later developing into growth arms by screw dislocation spawning of crystallites. At intermediate growth velocities, stacks of lamellae develop rapidly. The splaying apart of adjacent crystals and growth arms is abundant. The operation of growth spirals was observed directly in this growth velocity range. The crystals formed by the giant screw dislocations diverge immediately from the original growth direction, providing a source of interlamellar splaying. At low and intermediate velocities, the front propagates by the advance of primary growth arms, with the regions between the arms filled in by arms growing behind the primary front. At the highest velocity observed here, the formation of lamellar bundles and immediate splaying results in recognizable spherulites developing at the earliest stages of crystallization. The change from linear growth to splaying and nonlinear growth are qualitatively explained in terms of driving force, elastic resistance and the presence of compositional and/or elastic fields in the melt. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. B Polym. Phys. 36: 2311-2325, 1998
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 5
    Electronic Resource
    Electronic Resource
    Effects of treatment on the surface composition and energy of carbon fibers (1995)
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 16 (1995), S. 284-287 
    Details
    ISSN: 0272-8397
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The surface composition and energy of carbon fiber has been carefully analyzed and quantified. Untreated, AU, surface-treated, AS, and heat-treated AHT fibers were all studied. AS fiber was surface-treated by an electrolytic oxidation process. AHT fiber was heat-treated at elevated high temperatures under vacuum. X-ray photoelectron spectroscopy (XPS or ESCA) was used to investigate the surface elemental concentration of carbon fibers. The corresponding surface free energies of these fibers were calculated from the contact angles measured by a dynamic contact angle analyzer. Results showed a strong correlation between the surface treatment and heat-treatment history and the surface chemistry of carbon fibers. After oxidation treatment, the surface free energy was increased by adding functional group elements (oxygen and nitrogen). However, these added elements could be removed by high temperature treatment under vacuum. The diffusion of O, N, and Na was discussed. The correlation between oxygen and nitrogen concentration and carbon fiber surface free energy has been plotted. These fibers would be used to quantify the relationship between carbon fiber surface free energy and the interfacial shear strength of the fiber-polymer interface.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pc.750160404
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Influence of bond interchange reactions on mechanical behavior of solid poly(ethylene terephthalate) (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 34 (1996), S. 2307-2316 
    Details
    ISSN: 0887-6266
    Keywords: ester interchange ; small-angle neutron scattering ; poly(ethylene terephthalate) ; creep ; stress relaxation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Reported are a pair of studies exploring the possible role of transesterification during the deformation of poly(ethylene terephthalate) (PET) near its glass transition temperature. SANS experiments on PET-D/PET-H blends were carried out on films drawn according to the method of Petermann and Gohil at 70 and 90°C. In order to avoid effects of orientation on the SANS pattern, the measurements were made on liquid solutions made from the drawn material. The results show a decrease in the D-sequence length upon deformation, while the molecular weight of the chain is unchanged. This result indicates that bond exchange has taken place. Based upon the SANS results, an approximate activation energy in the 8-24 kcal/mol range is reported for bond interchange. To test the hypothesis that transesterification may play a role in the mechanical behavior of PET near Tg, creep measurements were carried out over a temperature range on either side of Tg. Activation energies obtained from time-temperature superposition shift factors showed a dual behavior: above Tg the activation energy matches those for diffusive processes in PET; below Tg the activation energy coincides with activation energies reported for exchange reactions in this material. The role of annealing prior to deformation is also reported, and it is shown that the activation energy increases rapidly with increasing annealing temperature. © 1996 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 7
    Electronic Resource
    Electronic Resource
    Study of bundle formation during crystallization in polymer blends (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 873-888 
    Details
    ISSN: 0887-6266
    Keywords: crystallization ; polymer blends ; pattern formation ; numerical simulation ; syndiotactic polystyrene ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The development of texture which exists in polymer spherulites grown from single phase melts containing an appreciable amount of noncrystallizable material was investigated. This texture generally consists of lamellar bundles separated by amorphous regions, both of which are typically 0.1-1 μm thick. A space-time finite element model previously developed by us was used to simulate the growth of a group of polymer lamellae. The model determines the impurity concentration field in the melt surrounding the growing lamellae and tracks the growth of each lamella. Important variables are the initial melt concentration of noncrystallizable material, the mass diffusion coefficient of noncrystallizable species, lamellar thickness, long period, and the rate of molecular attachment at the growth front. Under certain conditions, bundles did indeed develop during the simulations. These results were used to predict bundle thicknesses. The predictions of bundle texture were compared to actual textures observed in blends of syndiotactic and atactic polystyrene. It was found both experimentally and numerically that bundle thickness was a strong function of crystallization temperature and a relatively weak function of both the initial composition of noncrystallizable species and the degree of crystallinity of the lamellar stack. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 873-888, 1998
    Additional Material: 25 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 8
    Electronic Resource
    Electronic Resource
    A SPACE-TIME FINITE ELEMENT MODEL TO STUDY THE INFLUENCE OF INTERFACIAL KINETICS AND DIFFUSION ON CRYSTALLIZATION KINETICS (1997)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 40 (1997), S. 2679-2692 
    Details
    ISSN: 0029-5981
    Keywords: space-time finite elements ; phase transformation ; crystal growth ; polymer blend ; numerical simulation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: We present a space-time finite element formulation to study the cooperative growth of adjacent needle-like crystals in a two-dimensional, binary melt. It is assumed that the system is isothermal and that the compositions of the melt and the crystals are different. The growth rate of the crystals is taken to be a function of the melt composition in front of the growing crystals, and the composition of the melt as a function of space and time is determined by the diffusion equation. The positions of the growth fronts of each crystal are tracked. Good agreement is found between the numerical solution of an approximated one-dimensional problem and an analytical solution. Numerical results of the simulation of the growth of isolated and adjacent crystals are presented. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...