Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Abstract New semicrystalline polyimide/oligoimide blends, designated for matrices in carbon fiber‐reinforced composites, were developed. A specific advantage of the proposed polyimides is their ability to crystallize from the melt, therein retaining their crystallinity throughout the manufacturing process. The generat…
Abstract Poly(3‐hydroxybutyrate) (PHB)/poly(glycidyl methacrylate) (PGMA) blends with the PGMA content up to 30 wt % were prepared by a solution‐precipitation procedure. The thermal decomposition of PHB/PGMA blends was studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and differenti…
The thermal conductivity of diamond crystals with different isotope contents is evaluated in the framework of a microscopic model that considers acoustic- and optical-phonon branches. The phonon Boltzmann equation is solved iteratively, with the phonon wave vectors taken in the real Brillouin zone and the three-phonon…
The polycondensation of [3-(methacryloxy)propyl]trimethoxysilane was performed in bulk, using 98 wt % formic acid (molar ratio HCOOH/Si = 3 or 6), at 50 or 70 °C, for periods of time of up to 1 month. The resulting silsesquioxanes (SSOs) were characterized by 1 H NMR, FTIR, SEC, UV−MALDI−TOF MS (linear, reflector, and…
This colloquium discusses the atomic structure of carbon nanotubes as deduced from high-resolution electron microscopy and electron diffraction in transmission through a single nanotube. The principal features of the observed micrographs are interpreted in terms of the cylindrical, chiral geometry of the atomic distri…
Fabrication of an oxide−oxide nanocomposite, containing a homogeneous dispersion of NdAlO 3 nanocrystals in an Al 2 O 3 matrix, is achieved by employing a single molecular compound, [NdAl 3 (OPr i ) 12 (Pr i OH)], in the sol−gel process. X-ray diffraction patterns of the composite material show NdAlO 3 to be the only…
In this study, bubble production in a glass of champagne was used as a common tool to illustrate and better understand the nonclassical heterogeneous bubble nucleation from pre-existing gas cavities, referred as type IV nucleation in a recent review article (Jones et al. Adv. Colloid Interface Sci . 1999, 80, 27−50).…
Ultrafast optical switching from an ionic ( I) to a neutral ( N) state in TTF-CA was observed in femtosecond reflection spectroscopy. Charge transfer excitation in the I phase produces N donor ( D0) acceptor ( A0) strings within 2 ps. These initial N states decay with a lifetime of 300 ps at 4 K, but rather multiply l…
We numerically study the potential energy landscape of a fragile glassy system and find that the dynamic crossover corresponding to the glass transition is actually the effect of an underlying geometric transition caused by the vanishing of the instability index of saddle points of the potential energy. Furthermore, w…
This book presents an introduction to the theory of electronic transport in the solid state. The author starts with a reminder of the quantum theory of condensed matter and then concentrates on carrier transport itself. A wide range of subtopics is touched upon in different chapters, e.g. transport in bulk samples and…
Reaction mechanisms between titanium isopropoxide and deuterated water in the atomic layer deposition (ALD) of TiO2 at 150–350 °C were studied using a quartz crystal microbalance (QCM) and a quadrupole mass spectrometer (QMS). The temperature had no marked effect on the total amount of the main gaseous by-product (CH3…
Fully dense doped-ZnO varistors with sub- micrometer grain size (see Figure for a TEM image) can be fabricated by a strategic two-stage, one-cycle, thermal processing method at temperatures as low as 825 °C. The nonlinear coefficients α of such fully dense varistors are as high as 270, which is more than one order of…
Due to the effects of surface electromigration, waves can propagate over the free surface of a current-carrying metallic or semiconducting film of thickness h_0. In this paper, waves of finite amplitude, and slow modulations of these waves, are studied. Periodic wave trains of finite amplitude are found, as well as th…
We study the light transmission in two-dimensional photonic crystal waveguides with embedded nonlinear defects. First, we derive the effective discrete equations with long-range interaction for describing the waveguide modes, and demonstrate that they provide a highly accurate generalization of the familiar tight-bind…
A new kind of memory effect on low frequency dielectric measurements on plexiglass (PMMA) is described. These measurements show that cooling and heating the sample at constant rate give an hysteretic dependence on temperature of the dielectric constant $ε$. A temporary stop of cooling produces a downward relaxation of…
We investigate the formation of spiral crack patterns during the desiccation of thin layers of precipitates in contact with a substrate. This symmetry-breaking fracturing mode is found to arise naturally not from torsion forces, but from a propagating stress front induced by the fold-up of the fragments. We model thei…
We propose a new method to characterize the geometrical texture of a granular packing at the particle scale including the steric hindrance effect. This method is based on the assumption of a maximum disorder (entropy) compatible both with strain-induced anisotropy of the contact network and steric exclusions. We show…
Current-carrying and superconducting systems can be treated within density-functional theory if suitable additional density variables (the current density and the superconducting order parameter, respectively) are included in the density-functional formalism. Here we show that the corresponding conjugate potentials (v…
We present an O(N) algorithm to study the vibrational properties of amorphous silicon within the framework of tight-binding approach. The dynamical matrix elements have been evaluated numerically in the harmonic approximation exploiting the short-range nature of the density matrix to calculate the vibrational density…
We have measured the longitudinal resistivity and the Hall resistivity in the ab-plane of highly c-axis-oriented MgB2 thin films. In the normal state, the Hall coefficient (R_H) behaves as R_H ~ T with increasing temperature (T) up to 130 K and then deviates from that linear T-dependence at higher temperatures. The T^…