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。
The E.S.R. spectrum of an electron irradiated, type IIa diamond has been studied after it had been annealed at various temperatures up to 1400°C. Six sets of lines were identified following anneals in the temperature range 700°C–1000°C. They all arose from centres with ⟨110⟩ symmetry and a spin of 1. The centres are t…
The results of wide- and small-angle X-ray studies on bulk vulcanizates of natural rubber are described. At room temperature no discrete X-ray peaks occur at small angles, even for highly strained (700%) specimens for which a significant degree of crystallinity is present at room temperature. Below the isotropic melti…
Abstract A battery of characterizational tests have been performed on a systematically varying series of segmented polyurethanes. These tests include small angle light scattering (SALS), small angle and wide angle x‐ray diffraction, optical and electron microscopy, and mechanical testing (both tensile and dynamic). Ob…
A theory is developed to describe the shape of a long thin elastic film peeling from a rigid substrate under a constant load. The theory is verified by static measurements of spring steel strip and by slow peeling experiments using rubber and paint films. Extension of the theory to the case of viscoelastic peeling fil…
Abstract not Available.
A detailed study has been made of the deformation modes which operate in polyethylene single crystals when drawn on a Mylar substrate. The orientation relationships associated with the stress-induced twinning and monoclinic phase transformations have been determined by electron diffraction and compared with prediction…
The weak-beam technique of electron microscopy (Cockayne, Ray and Whelan 1969) has been used to image the fourfold dissociation of superlattice dislocations in a DO3-ordered Fe-26 at.% Al alloy. Values of 77±12 and 85±16 erg cm-2 have been obtained for the first and second nearest-neighbour antiphase boundary energies…
Exchange splittings of $3s$ electrons in $3d$-group transition-metal compounds have been obtained by x-ray photoemission spectroscopy. The data for the difluorides exhibit the expected dependence on $d$-shell spin and $s$-electron binding energy, and yield a $3s$ splitting of 2.6 eV/spin. Data on a series of manganese…
At a late stage in sensescence cucumber cotuledons lose fresh weight rapidly; at the same time there is an increase in apparent free space and large quantities of electrolyte leak out when discs of cotyledon tissue are floated on water. It is concluded that tonoplast and plasma membrane become leaky at this time. Phos…
Martensitic transfromation in TiNi alloys of the near-equiatomic composition has been studied by utilizing electron microscopy and diffraction under various thermal treatments. It has been observed that the martensitic transformation is associated with the variants of the product. Two orientations of the martensitic p…
The usual way to align a liquid crystal layer homogeneously is rubbing the substrate, wherby micro-grooves are produced. We investigated the orienting influence of micro-grooves of variable density using different substrate materials and different liquid crystals. Some theoretical considerations concerning the alignin…
A series of liquid crystalline materials comprising substituted phenyl 4-benzoylioxybenzoates were prepared. These compounds may be viewed as derivatives of the unsymmetrical molecule, p-hydroxybenzoic acid. The mesomorphic properties of these new compounds were compared with the more symmetrical analogs derived from…
Abstract Die metallreichen Oxide (mit 0 < 0/M < 0,5) von Rb mid Cs werden mit speziell dafür entwickelten präparativen, thermoanalytischen und röntgeno‐graphischen Verfahren untersucht. – Die bislang erhaltenen extrem luftempfindlichen Verbindungen besitzen die Zusammensetzungen Rb 6 O, Rb 9 O 2 , Cs 7 O und Cs…
The electronic contribution to the heat capacity of ${\mathrm{V}}_{1.97}$${\mathrm{O}}_{3}$, ${\mathrm{V}}_{7}$${\mathrm{O}}_{13}$, and ${\mathrm{V}}_{\mathrm{O}.86}$${\mathrm{W}}_{0.14}$${\mathrm{O}}_{2}$ is very large, with $\ensuremath{\gamma}=(130\ifmmode\pm\else\textpm\fi{}3), (80\ifmmode\pm\else\textpm\fi{}5), \…
The heat capacity of N-(2-hydroxy-4-methoxybenzylildene)-4′-butylaniline(2,4-OHMBBA) with a purity of 99.393 mole % was measured between 13 and 375 K. The Melting point T m was 314.30 K, and the enthalpy and the entropy of fusion were 22.405 kJ mol−1 and 71.425 J K−1 mol−1, respectively. The temperature of transition…
The three-dimensional structure of the radical-cation radical-anion salt from 2,2′-bi-1,3-dithiole (1) and 7,7,8,8-tetracyanoquinodimethane (2) has been determined by X-ray diffraction methods; the structure is composed of segregated columnar stacks of cations and anions.
Abstract Glycine N-methyltransferase, an enzyme which methylates glycine in the N-position to yield sarcosine, has been purified to homogeneity from rabbit liver and partially characterized. The enzyme has a molecular weight of 123,500 as determined by sedimentation equilibrium centrifugation and consists of 3 to 4 no…
At the Freedericks transition of a nematic slab, the molecules can rotate by two different ways, giving rise to adjacent domains separated by a wall. We present observations on the structure and dynamics of these walls at magnetic fields above the transition. The local distortion through the wall agrees with theoretic…
Single-domain samples of cholesteric liquid crystals and of the recently reported twisted smectic C phase may have identical optical properties for light incident in the direction of the axis of twist. A single Bragg-reflection band exists for either type of liquid crystal in that case. However, with obliquely inciden…
The oxidative cleavage of haemin in aqueous pyridine under various conditions (ascorbic acid–oxygen; hydrazine–oxygen; and ascorbic acid–hydrogen peroxide) gives four isomeric biliverdins of the IX series which have been isolated (from a much improved ascorbic acid–oxygen reaction) as their crystalline dimethyl esters…