Materials Literature
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By applying fluorescence together with DSC and WAXD, structure analysis for a thermotropic liquid-crystalline (LC) polyester (PB-10), prepared from 4,4‘-dihydroxybiphenyl and sebacic acid, containing 10 methylene units, was carried out. The PB-10 shows two enantiotropic transitions: One is the crystal−smectic H transi…
Three iron complexes of the meso-dioxo derivative of octaethylporphryin (trans-H(2)OEPO(2)) were characterized by X-ray diffraction. Green ClFe(III)(trans-OEPO(2)).1.5C(6)H(6) crystallizes in the monoclinic space group P2(1)/c with a = 13.766(3) Å, b = 19.075(3) Å, c = 15.217(3) Å, beta = 99.87(2) degrees at 123 K wit…
A direct current glow discharge mass spectrometer has been used for the analysis of Macor, a nonconducting glass ceramic. To overcome the problem of the conductivity barrier, a tantalum secondary cathode was placed in front of the flat Macor sample. Although the sample characteristics of Macor (the electrical conducti…
The structural and energetic consequences of nonbonded interactions between axial ligands and minimally superstructured borylated iron bis(dioxime) complexes are described. Structural data for 20 low spin axially ligated derivatives are compared. Complexes of Fe((DMG)BPh 2 ) 2 (Py)L, L = NH 3, TCNE, PMePh 2, and Py an…
Crystalline silicon is the principal semiconducting material and will doubtless continue to be the mainstay in the electronics industry for the foreseeable future. However, silicon is lacking the properties necessary to emit light efficiently and thus cannot be employed for optically active or optoelectronic applicati…
Optical and time-resolved EPR(TREPR) studies were made on the excited states of fluorine-substituted magnesium tetraphenylporphines (MgF−TPPs) including related Mg porphyrins. From the analyses of TREPR spectra it was found that the zero-field splitting parameter, D, increased with an increasing number of substituents…
In this paper we shall be interested in establishing existence of certain equilibria of the Cahn-Hiliard equation. 20 refs.
It has been mentioned that nitrogen enhances the corrosion resistance of the martensitic stainless steels. In this work, by means of electrochemical and mass loss tests, the corrosion resistance of three experimental martensitic stainless steels, with partial substitution of carbon by nitrogen were investigated. Marte…
The structures of ten related oxypregnane-oligoglycosides stephanosides A (1), B (2), C (3), D (4), E (5), F(6), G (7), H (8), I (9), and J (10) from the fresh stem of Stephanotis lutchuensis var. japonica (Asclepiadaceae)were elucidated on the basis of a detailed study of their high-field 1H- and 13C-NMR spectra. All…
The thermal decomposition of NF 3 by various oxides was investigated using gas chromatography, BET surface areas, and X-ray powder diffraction. The decomposition of NF 3 using alumina can occur at temperatures as low as 100 °C, with steady complete conversion for almost 4 h at 400 °C. The reaction is shown to be stoic…
Image-processing techniques for measuring the fibre-orientation distribution in a nonwoven fabric are described. The digitised image of the surface of a fabric is progressively simplified by a line operator and edge-smoothing and thinning operations to produce an image in which fibres are represented by curves of one…
NO selective reduction by CH4 over Ga2O3 catalysts is a structure-sensitive reaction depending on the local structure of Ga2O3; low-coordinate Ga ions are responsible for higher activity.
Configuration interaction (CI) spaces obtained from the full CI space by imposing arbitrary restrictions on the occupancies of molecular orbital (MO) groups are studied. It is proved that such restricted spaces are in a certain sense “closed.” Namely, in the course of the Hamiltonian matrix construction the excitation…
Reaction of Fe(OH) 3 with 2 equiv of catechol (Cat) and 1 equiv of NaOH in aqueous solution produces violet crystals (monoclinic unit cell, space group C 2/ c, with a = 22.544(9) Å, b = 12.949(6) Å, c = 22.459(9) Å, β = 91.10(3)°, V = 6555(5) Å 3, Z = 4, and R = 0.039) of (Ph 4 P) 2 [Fe 2 (Cat) 4 (H 2 O) 2 ]·6H 2 O. X…
The application of the desyl or 2-oxo-1,2-diphenylethyl moiety as a photolabile ligand for the release of phosphates such as cAMP and inorganic phosphate (P i ) 1,2 is extended to include selected excitatory amino acids. The synthesis and photochemical studies of N - and O -desyl-caged versions of the endogenous amino…
Isotactic (i) and syndiotactic (s) polypropylenes (PP) have been successfully incorporated into the channels of their inclusion compounds (IC) with urea (U). The IC's were obtained by cocrystallization following the addition of a warm toluene solution of polymer to a warm solution of urea in methanol. The white crysta…
The Frank elastic constants of lyotropic polymer liquid crystals are formulated using an equivalent freely-jointed chain model, which can be uniquely defined by the parameters of the corresponding wormlike chain and the polymer concentration. The contribution of the higher virial terms to the elastic constants was tak…
Different reconstructions of the polar, cation-terminated (100) surface of Cu 2 O have been investigated. All surfaces have been fully relaxed employing a pair-potential and shell-model description of the interactions within the crystal. A (1 × 1) missing-row reconstruction gave the lowest surface energy, while the ex…
The phase separation processes occurring in poly( l -lactide) (PLLA)−chloroform−methanol mixtures and poly( dl -lactide) (PDLLA)−chloroform−methanol mixtures have been studied using differential scanning calorimetry, cloud point measurements, and optical microscopy. It is demonstrated that liquid−liquid demixing occur…
Two very different molecular shapes are formed using the ligand 1,3,5-tris(diphenylphosphino)benzene (L); polymeric chains form through Au⋯Au contacts in the crystals of [(ClAu)3L], while the metallocyclophane [(PtCl2)3L2] self assembles from five components when L and [PtCl2(cod)] are combined in a 2:3 molecular rati…