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。
Given our current expertise, and the certain future devel-opments in genetically altering organisms to produce proteins of modified structure and function, the concept of protein engineering is nearing reality. Similarly, our ability to describe and utilize protein structure and to define interactions with ligands has…
The electron-density map of an Si crystal is drawn by the maximum-entropy method (MEM) with 30 structure factors which were determined very accurately on an absolute scale by the Pendellösung method [Saka & Kato (1986). Acta Cryst. A42, 469-478]. It is shown that the following three beneficial points arise from the us…
A review of the observations of indentation‐induced fracture suggests that there is no simple generalization which may be made concerning crack initiation sequences. Here, we investigate the material dependence of the initiation sequence of indentation cracks (cone, radial, median, half‐penny, and lateral) using an in…
Peer reviewed: Yes
The use of the thermoelastic martensitic transformation and its reverse transformation has recently been proposed and demonstrated for several active control ap plications. However, the present constitutive models have lacked several important funda mental concepts that are essential for many of the proposed intellige…
The first conducting polymer was reported in 1977 when Shirakawa, MacDiarmid, Heeger and other coworkers1 discovered that polyacetylene (Fig. 1), an organic polymer and electrical insulator, could be converted into an electrical conductor by absorbing a small amount of iodine. Since then, active research has led to th…
The synthesis of highly conducting polyacetylene in the late seventies inaugurated an era of extensive studies of electronic structure and transport in organic polymers. The recent attainment of conductivities in metallic polyacetylene comparable to that of copper is the outcome of major advances in the theoretical un…
Using simple thermodynamic arguements, it is shown that sharp concentration gradients occurring during diffusive mixing of multilayer composites facilitate amorphization by solid-state reaction by reducing or suppressing the driving force for crystallization \ensuremath{\Delta}${\mathit{G}}_{\mathit{a}\mathit{c}}$. As…
High-resolution x-ray and optical studies were peformed on oriented samples of the recently discovered smectic-${\mathit{A}}^{\mathrm{*}}$ phase. We confirm that this phase exhibits smectic-A layers as well as a macroscopic helical strcucture with the helical axis parallel to the layer planes. Furthermore, we demonstr…
The concept of mean-field rigidity percolation at average coordination number 〈r〉=2.4 in covalently bonded inorganic glasses is shown to be relevant to the liquid-state behavior of glass-forming chalcogenide systems. In particular it correlates with remarkable variations in ``fragility'' and excess heat capacity which…
Abstract Some organic crystalline solids that comprise highly polar molecules and that form non-centrosymmetric crystal structures exhibit second-order nonlinear optical properties and laser-damage thresholds that are potentially superior to those of currently available inorganic systems. This realization has led to a…
Ultrasound causes high-energy chemistry. It does so through the process of acoustic cavitation: the formation, growth and implosive collapse of bubbles in a liquid. During cavitational collapse, intense heating of the bubbles occurs. These localized hot spots have temperatures of roughly 5000 degrees C, pressures of a…
This book deals with the methods of X-ray production at a level which is accessible to advanced undergraduates and researchers who use X-rays. It also discusses the fundamentals of these physical properties from an experimental viewpoint which is not covered in more specialised texts. The book begins with a survey of…
Abstract A mathematical model for simulation of industrial process of solid state polycondensation of poly(ethylene terephthalate) (PET) has been developed. The model eliminates errors evident in the earlier models by proper formulation. The model results have been validated by experimental data in the literature. It…
The author presents a formalism for the study of the effects of alloy disorder at crystalline interfaces on the phonon boundary scattering cross section. The disordered region is treated within the coherent potential approximation adapted to the interface geometry. The formalism is based on t-matrix scattering theory…
We have investigated the epitaxial growth of Zn1−x CdxSe epilayers and ZnSe/Zn1−x CdxSe superlattices (0≤x≤1) on (100)GaAs. Although thick epilayers of Zn1−x CdxSe are prone to defect formation with increasing Cd content, the structural and optical characteristics improve remarkably when Zn1−x CdxSe is in the form of…
The critical single domain size for a uniaxial magnetic material under variable external conditions (temperature and magnetic field) is discussed.
It is proposed that the structure of a new layer AB, which forms between the components A and B, is defined by parameters of two-stage interfacial reactions. The two stages, namely transition of A atoms through the AB/B boundary and rearrangement of atoms in B into AB, have independent rates. In the initial stage of t…
The crystal structures of NH 4 SCN are determined in the tetragonal phase I (122°C) and the orthorhombic phase II (100°C, 110°C and 115°C) from X-ray diffraction data. In phase I, SCN - ion is in disordered state taking two equivalent configurations. In phase II, the ordering of SCN - ion correlates to the spontaneous…
Cristallisation dans P2 1 /c avec a=5,767, b=10,574, c=6,835 A, β=105,04 o , z=4; affinement jusqu'a R0,062. L'arrangement atomique est identique a celui de NaBUO 5 orthorhombique, sauf en ce qui concerne l'ion alcalin. Les ions lithium sont, en effet, situes dans les sites tetraedriques, tandis que les ions sodium se…