Materials Literature
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Porous, low dielectric constant polyimide films have been made by a “nanofoam” approach. The pore sizes generated in the polymer films are in the tens of nanometers range, hence the term “nanofoams”. The nanoporous foams are generated by preparing triblock copolymers with the majority phase comprising polyimide and th…
The dynamic growth processes of lamellae and spherulites of a polymer (BA-C8) synthesized by condensation polymerization of bisphenol A and 1,8-dibromooctane were directly observed using an atomic force microscope at 25 ± 1 °C. The phase shift measured at the tip of growing lamellae is lower than the phase shifts of t…
We present a theory of the resonant inelastic x-ray scattering (RIXS) to study electronic excitations in orbital ordered manganites. The charge and orbital excitations of the Mn 3d electron are caused by the Coulomb interactions in the intermediate scattering state. The scattering cross section is formulated by the Li…
In a recent paper (2000 \QTR{it}{J. Phys.: Condens. Matter} \QTR{bf}{12} L133) Lee \QTR{it}{et al.} have studied the transport properties of Pr$_{0.65}$Ca$_{0.35}$MnO$_{3}$ thin films. They claimed that they are able to controlled the charge-ordered (CO) state by the lattice strains. We propose herein another alternat…
Comment on the paper of T.Bachels, H. J. Güntherodt and R.Schäfer : "Melting of Isolated Tin Nanoparticles".
A microscopic theory for the ubiquitous phenomenon of static friction is presented. Interactions between two surfaces are modeled by an energy penalty that increases exponentially with the degree of surface overlap. The resulting static friction is proportional to load, in accordance with Amontons' laws. However the f…
We have found the equations that determine the self-adjoint extensions, and thus the boundary conditions, of the differential operator used in the multi-band k.p-theory, when the coefficients in the Kane-matrix are piecewise constant. Both the one-dimensional and the three-dimensional case have been investigated. A nu…
The transition from a liquid to a glass in colloidal suspensions of particles interacting through a hard core plus an attractive square-well potential is studied within the mode-coupling-theory framework. When the width of the attractive potential is much shorter than the hard-core diameter, a reentrant behavior of th…
Processes: Technical Textiles Market-An Overview. Technical Fibres. Technical Yarns. Technical Fabric Structure: Woven Fabrics. Knitted Fabrics. Non-woven Fabrics. Technical Textile Finishing. Coating. Colouration. Areas of Application: Heat and Flame Protection. Textile-Reinforced Composite Materials. Waterproof/Brea…
This Account reports the synthesis and characterization of dendrimer-encapsulated metal nanoparticles and their applications to catalysis. These materials are prepared by sequestering metal ions within dendrimers followed by chemical reduction to yield the corresponding zerovalent metal nanoparticle. The size of such…
Optical absorption associated with the one-dimensional joint density of states of an intersubband transition in bismuth nanowires is reported. The previously observed strong absorption in bismuth nanowires at ∼1000 cm−1 is here shown to depend on the wire diameter and on the polarization of the incident light. The abs…
Weak anchoring of liquid crystals on solid substrates is usually dominated by the surface memory. We show that the memory can be removed by surface passivation by silane molecules. We realize planar, azimuthally degenerated, and memory-free anchorings without pretilt.
Very short nanofibers containing only a few nanobells have been produced from nitrogen-doped carbon nanotubes by two methods, H2 plasma treatment, followed by grinding and oxidation with acidified potassium permanganate. The length of these short nanofibers can be controlled to give a wide range of sizes. The shortest…
We dispersed crystalline Si into a colloid of ultrasmall nano particles (∼1 nm), and reconstituted it into microcrystallites films on device-quality Si. The film is excited by near-infrared femtosecond two-photon process in the range 765–835 nm, with incident average power in the range 15–70 mW, focused to ∼1 μm. We h…
We report a novel form of planar magnetic colloidal crystals formed by coated magnetic microspheres floating on a liquid meniscus. Under an external magnetic field, the balance between the repulsive magnetic interaction and the "attractive" interaction, due to the weight of the particles projected along the surface ta…
We present a detailed study of the geometry of the atomic clusters encountered in icosahedral F-type quasicrystals using the cell decomposition of the prototypic atomic surfaces introduced several years ago for modeling i-AlCuFe. This includes an exhaustive and quantitative characterization of the geometrical features…
We show the growth of epitaxial NiMnSb(001) thin films, a half-metallic ferromagnet, on GaAs(001) by molecular-beam epitaxy. The Sb content of the films strongly depends on the Sb flux. Sb-deficient films show a reduced magnetization and the formation of a Mn2As interface layer. Stoichiometric films exhibit the bulk l…
Dielectric properties of ceramic samples of (1−x)SrTiO3–xSrMg1/3Nb2/3O3 and (1−x)SrTiO3–xSrSc1/2Ta1/2O3 solid solutions were studied at x⩽15% and x⩽10%, respectively. The real and imaginary parts of the dielectric constant were measured at frequencies between 10 Hz and 1 MHz and in a temperature range of 4.2–300 K. Re…
The medicinal plants used for the treatments of skin diseases and related problems in Northeastern India were reviewed based on the ethnobotanic reports. Of the 275 plant species examined, 224 species have been used for treatment of specific human ailments such as allergies, burns, cuts and wounds, inflammation, lepro…
We investigate the hydrodynamic interaction in suspensions of charged colloidal silica spheres. The volume fraction as well as the range of the electrostatic repulsion between the spheres is varied. Using a combination of dynamic x-ray scattering, cross-correlated dynamic light scattering, and small angle x-ray scatte…