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 flexoelectric behaviour of a hypertwisted chiral nematic bimesogenic liquid crystal is presented. Through detailed electro-optic measurements, with particular emphasis on the switching properties, we demonstrate remarkably high optical axis tilt angles. The material studied possessed a room temperature nematic pha…
An aromatic polyimide bearing photoreactive 4-(2-(4-oxyethylenyloxyphenyl)vinyl)pyridine side groups was synthesized and characterized. The polymer is stable up to 300°C and soluble in organic solvents, giving thin films in good quality. When exposed to UV light, it reorients favorably with an angle of 98° with respec…
New series of ferroelectric liquid crystalline materials containing methyl and methoxy lateral groups on the aromatic ring of the core unit, as well as non-substituted materials have been synthesised. All compounds exhibit a wide temperature range of the ferroelectric chiral SmC* phase. A low temperature ferroelectric…
Chloromuconate cycloisomerases of bacteria utilizing chloroaromatic compounds are known to convert 3-chloro-cis,cis-muconate to cis-dienelactone (cis-4-carboxymethylenebut-2-en-4-olide), while usual muconate cycloisomerases transform the same substrate to the bacteriotoxic protoanemonin. Formation of protoanemonin req…
Solid state diffusion bonding of Inconel 718 has been studied. Mechanical tests and metallographic examinations were used to evaluate the joint quality. The effect of bonding time, temperature, and pressure on the joint integrity was assessed. The results showed thatpartial recrystallisation occurs in joints bonded at…
The immersion test method, potentiodynamic cyclic anodic polarization, scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy (XPS) techniques were used to study corrosion behavior of stainless steels (SS) and nickel-based alloys in acetic acid (CH3COOH; HAc) solutions containing bromide ions. In 50%…
The high-pressure behavior of semiconducting cadmium thiogallate CdGa2Se4 with the defect chalcopyrite structure (I4, Z=2) is studied by in situ angle-dispersive synchrotron X-ray powder diffraction and optical reflectivity measurements in a diamond anvil cell at room temperature. At 21 GPa an order–disorder phase tra…
Abstract The structure of a 2-chain helical form of sulphur with 9 atoms per unit-cell has been determined from powder synchrotron x-ray diffraction data obtained at 3 GPa and 400ºC, using a combination of global optimization, simulated annealing and Rietveld refinement techniques. Final refinement of the structure in…
This work tries to give an answer to questions persisting over a decade in literature, concerning poly(3-alkylthiophene)s: polymorphism and phase stability related to the molecular masses, their distribution, the degree of regioregularity, the length of the side chain, and its nature. In fact we have studied, by means…
Abstract Crystal-structure refinements were done on Li-bearing muscovite-2M1 crystals from microgranite and granitic pegmatite rocks in order to characterize their crystal chemistry and their relationships with muscovite and trioctahedral lithium-containing micas. In addition to the substitution mechanism [6]Li+ [6]Al…
Abstract The vibrational properties of WO 3 ceramics in the 30–300 K temperature range were probed by Raman spectroscopy. Starting with WO 3 ceramics at room temperature presenting monoclinic (V) and triclinic (VI) mixed phases, structural transitions related to decreasing temperature were observed. At low temperature…
Low-temperature photoluminescence (PL) of unactivated KDP crystals under selective synchrotron excitation is for the first time measured with subnanosecond time resolution. Time-resolved PL (2–6 eV) and PL excitation (4–35 eV) spectra, as well as PL kinetics, are measured at 7 K. From the acquired experimental data, l…
While the kinetics of intermetallic phase formation in duplex stainless steel have been extensively studied for a wide range of compositions, relatively little research has been done on the mechanisms by which the phases nucleate and grow. In this research the emphasis was on the diffusional growth of the sigma (σ) an…
Abstract The crystal structures of flux-grown Li 2 (MoO 4 ), LiY(MoO 4 ) 2 and LiNd(MoO 4 ) 2 were solved and refined from single-crystal intensity data collected with a four-circle diffractometer (Mo K α X-radiation, CCD area detector, room temperature). Li 2 (MoO 4 ) is isostructural with phenacite, Be 2 (SiO 4 ) an…
About 20 years ago, a technological innovation process started that eventually led to the affirmation of magnetic resonance imaging (MRI) contrast agents, which are used today in about 25% of all MRI procedures, as medical diagnostic tools. The process began with exploration of various technical possibilities and the…
Abstract High molar mass medium density polyethylene (MDPE) compounds containing magnesium hydroxide filler, surface‐treated by a range of fatty acid coatings of variable aliphatic chain length were injection molded and subjected to mechanical property evaluation. Surface treatment modifies yield stress and modulus, w…
Abstract The use of a tetrafunctional epoxy‐based additive to modify the molecular structure of poly(ethylene terephthalate) (PET) was investigated with the aim of producing PET foams by an extrusion process. The molecular structure analysis and shear and elongation rheological characterization showed that branched PE…
The liquid crystals have been discovered in 1888. Until about 1900 only few mesogenic compounds were known. Daniel Vorländer started his work on liquid crystals about one century ago and he may be called “father of liquid crystal chemistry”. By systematical syntheses of compounds with predetermined geometrical shape h…
The process of stimulated Raman scattering (SRS) allows to convert laser emission wavelengths of materials providing suitable molecular or lattice modes which contribute to the third order nonlinear optical susceptibility. SRS of known materials can produce Stokes or anti-Stokes shifts in the range of about 100 to 310…
Polydomain tetragonal ( t′ ) zirconia was deformed in compression along a 〈100〉 orientation at various temperatures between 500° and 1400°C. The stress‐strain curves showed a plateau corresponding to ferroelastic deformation, followed by plastic deformation at a higher yield stress level. In both ranges, the strain‐ra…