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。
A quantitative description of transition-metal bonding has been obtained through combined analysis of 9(1) K X-ray and 13(1) K time-of-flight neutron diffraction data. It is shown that a simple valence-orbital model is too crude an approximation adequately to describe the electron-density distribution of Ni(ND 3 ) 4 (…
The liquid‐crystalline behavior of rod‐like mesogens is normally associated with the formation of smectic layer structures. However, it is shown that the introduction of large hydrophilic groups in a lateral position, such as in the Figure, can lead to columnar mesophases. The formation of columnar mesophases by rod‐l…
We investigate critical points of the free energy E ε (u) of the Cahn–Hilliard model over the unit square under the constraint of a mean value ü. We show that for any fixed value ü in the so-called spinodal region and to any mode of an infinite class, there are critical points of E ε (u) having the characteristic symm…
Possible grain boundary structures and distributions in monoclinic zirconia are discussed. Crystallogeometrical analysis was employed to evaluate some special, low-energy boundaries in the material. A computer simulation was then used to model the grain boundary misorientation and character distributions based on cert…
Singlet oxygen (1O2), a highly reactive and toxic intermediate, may play a role in photo-induced aging. We examined singlet oxygen generation from hematoporphyrin (HP) with UV-A, by monitoring the emission at 1,268 nm corresponding to 1O2 --> 3O2. Singlet oxygen was formed HP-dose-dependently in this system. We then i…
Single-crystal magnetisation and polarised neutron diffraction (PND) measurements have been made for the complex cis-[ReCl 4 (NHCMeNHPh) 2 ]. At higher temperatures the magnetic behaviour is typical of such a rhenium-(IV) complex, with three unpaired spins (µ = 3.6 µ B ), an almost isotropic g-tensor of 1.86(1) and a…
Three N,N″-bis(amide) derivatives of H 5 dtpa (diethylenetriamine-N,N,N′,N ″,N″-pentaacetic acid), H 3 L 1 = bis- (isopropylamide), H 3 L 2 = bis(tert-butylamide) and H 3 L 3 = bis(benzylamide), were synthesized. Their protonation constants were determined by potentiometric titration in 0.10 mol dm -3 KCl and by NMR p…
In-situ deposition of conducting polypyrrole thin films on an insulating substrate has been achieved by chemical polymerization of pyrrole on a modified surface. The surface modification agent was a silane compound bearing a pyrrole group; C 4 H 4 NC 3 H 6 Si(OMe) 3 which attached to the SiO 2 -Si surface via molecula…
Mechanical damage to thin, protective oxide layers arises principally in service from differential strains produced by temperature changes. For typical alumina- or chromia-forming alloys, in-plane tensile stresses are developed within the oxide layer during upward temperature transients and compressive stresses are pr…
Liquid crystalline alkane-3,4-dienoates (allenylacetates) have been synthesized. Most compounds incorporate a heterocyclic 1,3,4-thiadiazole ring or a pyrimidine ring as a constituent of the rigid core. These axial chiral allene derivatives were at first obtained as racemic mixtures. Some of them were also synthesized…
Physical theories concerning the structures and properties of chiral smectic liquid crystals abound, however, very few are of practical use in the design and subsequent synthesis of materials. The development of macroscopic theories, although very useful in the explanation of physical phenomena, are not readily transf…
This paper reports the incorporation of a nonamphiphilic blue laser dye 2,2‘- p -phenylenebis(5-phenyloxazol), abbreviated as POPOP, in Langmuir−Blodgett (LB) films mixed with stearic acid (SA) and their spectroscopic properties. The surface pressure versus area per molecule isotherms of POPOP mixed with SA at differe…
Abstract The use of ozone and hydrogen peroxide for the simultaneous oxidation of nitrogen and sulfur oxides was studied in experiments carried out in a stirred cell. It was found that in a gas mixture, containing both nitrogen and sulfur oxides, only the nitrogen oxides are oxidized by ozone. Contrary to earlier resu…
In order to test the influence of ceramic morphology and particle size on the behaviour of the ceramic/polymer/drug composite α-Al 2 O 3 /poly(l-lactic acid)/poly(methyl methacrylate)/ibuprofen (α-Al 2 O 3 /PLLA/PMMA/IB) containing the antiinflammatory drug ibuprofen, have been studied. We have used α-alumina synthesi…
A detailed study of the wavelength dependence of the formation of lenslets by photo-expansion in chalcogenide glasses is reported. Photo-expansion in chalcogenide glasses offers a one-step fabrication process to record surface structures such as gratings and microlenses. The process is purely optical and requires no f…
Classical Powder Diffraction usually assumes samples with completely random orientation distribution of the crystallites. It can be generalized to non‐random orientation distribution (texture) by introducing a texture factor which enters the expression of the integral intensity directly and serves as a weight function…
An experimental and numerical study of solidification characteristics of a droplet on a horizontal cooled wall is reported. Pure water and molten salt were utilized as the testing liquids. The droplet was cooled under a variety of conditions such as wall temperature and initial liquid temperature in a static atmospher…
Heat treatment of 60CaO·27Al 2 O 3 ·13Fe 2 O 3 glass resulted in a precipitation of antiferromagnetic dicalcium ferrite (Ca 2 Fe 2 O 5 ) and mayenite (12CaO·7Al 2 O 3 ). The effective magnetic moment of the sample decreased from 2.0 to 1.7 µ B owing to the precipitation of antiferromagnetic particles. The Mössbauer sp…
Abstract Films of bacterial poly(3‐hydroxybutyrate), obtained by crystallization from the melt at different temperatures up to 120°C, were investigated by powder X‐ray diffraction analysis and optical microscopy. With increasing crystallization temperature ( T c ) the diffraction patterns differed more and more from t…
Strong exciton coupling occurs between adjacent pairs of naphthyl chromophores in the chiral sodium and europium complexes of L 1 ; in the constitutionally isomeric complexes of L 2 , intramolecular excimer formation is observed and both sets of Eu complexes give a well defined, metal-based circularly polarised emissi…