Materials Literature
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Four series of photocrosslinkable-cum-flame retardant poly(benzylidene phosphoramide ester)s were synthesized from bis(4-hydroxy-3-methyoxybenzylidene) acetone, 2,5-bis(4-hydroxy-3-methoxybenzylidene)cyclopentanone, 2,6-bis(4-hydroxy-3- methoxybenzylidene)cyclohexanone and 2,7-bis(4-hydroxy-3-methoxybenzylidene) cyclo…
We have measured the temperature dependence of the absorption spectra in the band-edge region and the reflection spectra of the (CH 3 NH 3 ) 3 M 2 Br 9 (M:Sb,Bi) single crystals exhibiting serveral successive phase transitions. The dispersion-like reflection structure due to the band-edge exciton transition is observe…
Time-resolved photoluminescence measurements are performed on oxidized and fresh porous silicon at room temperature. Comparing the evolution of the nanosecond time-delayed photoluminescence (PL) in both cases, a new feature of the PL spectra is identified: a fast red band, present both in fresh and aged samples. The n…
The rhombohedral Pr2Fe17Hx compounds with the Th2Zn17 structure have been prepared for x=0–5. Their lattice parameters and Curie temperatures have been determined from powder x-ray diffraction and thermomagnetic measurements, respectively, and their Mössbauer spectra have been measured between 4.2 and 295 K. The Mössb…
The microwave heating technique is employed for obtaining high performance positive temperature coefficient of resistivity (PTCR) ceramics of Nb-doped BaTiO3 with a low resistivity at room temperature and a high resistivity jump above the Curie temperature. The grains of the BaTiO3:Nb ceramics prepared by microwave si…
The electrical conductivity of semiconducting magnesium vanadate glasses has been reported for a wide composition range in the temperature range of 80–500 K. The experimental results have been analyzed in the framework of different hopping models. It has been observed that the multiphonon assisted hopping model of sma…
This study utilized Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry, Thermogravimetric Analysis, Differential Scanning Calorimetry, X-Ray Diffraction, and Dielectric Analysis to assess the viscoelastic and structural properties of three generations of tert-butyl and methyl ester, amide-bas…
The atomic geometry of the Al(100)-$c(2\ifmmode\times\else\texttimes\fi{}2)$-Li phase formed by adsorption of $\frac{1}{2}$-ML Li on Al(100) at room temperature has been determined by analysis of extensive low energy electron-diffraction (LEED) measurements. The structure is found to be a binary surface alloy, in whic…
The compatibilizing effect of polypropylene (PP) grafted with hyperbranched polymers (PP–HBP) has been investigated in PP/polyamide-6 (PA-6) blends. Because of its high reactivity and diffusitivity, PP–HBP has been shown to be a more effective compatibilizer in decreasing the interfacial tension than the commonly used…
A systematic study on the synthesis, characterization, degradation, and drug release of fatty acid terminated poly(sebacic acid) (PSA) is reported. Fatty acid terminated sebacic acid polymers were synthesized by melt condensation of acetate anhydrides of linear fatty acids (C8–C18) and sebacic anhydride oligomers to y…
Ring-opening polymerization of 1,5-dioxepan-2-one initiated by 1,1,6,6-tetra-n-butyl-1,6-distanna-2,5,7,10-tetraoxacyclodecane was carried out in chloroform, dichloromethane, or 1,2-dichloroethane. Effects of reaction temperature, solvent, and monomer-to-initiator ratio were investigated. Polymerization kinetics showe…
We investigated temperature-dependent optical conductivity spectra of a ${\mathrm{Nd}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$ single crystal. We found that polishing and surface scattering effects on the ${\mathrm{Nd}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$ crystal surfaces could significantly distort the op…
47,49 Ti, 89 Y and 139 La NMR measurements have been performed to study local magnetic properties of the Mott-Hubbard insulators YTiO 3 and LaTiO 3 . In particular, the magnetic structure of the ferromagnetic (antiferromagnetic) state of YTiO 3 (LaTiO 3 ) is discussed based on the analysis of 47,49 Ti frequency-swept…
A large magnetoresistance appearing below the ${T}_{c2}\ensuremath{-}\mathrm{CDW}$ (charge-density wave) transition temperature in ${\mathrm{NbSe}}_{3}$ has been studied under various pressures including pressure above the critical pressure where the ${T}_{c2}\ensuremath{-}\mathrm{CDW}$ phase is suppressed totally. Th…
In the present article, the effects of Al, Zn, Fe, Ni, and Cu powders on the thermal degradation of waste polystyrene were studied. The results show that the catalytic effects of metal powders have a relationship with their activities. The catalytic effects increase with the increasing activities of metals. It is sugg…
We present a model describing the Urbach tail of exciton absorption spectra in ferroelectric materials with order-disorder-type phase transition. In addition to the thermal effect of exciton-lattice interactions, the internal Stark effect by the local electric field due to the displacement of protons is taken into acc…
A high-resolution magnetic circular dichroism (MCDA) study of the sharp 1.404-eV zero-phonon absorption line associated with interstitial nickel in high-pressure synthetic diamond is reported. A model is presented attributing the absorption to internal transitions within the ${3d}^{9}$ configuration of ${\mathrm{Ni}}_…
Director tilting of liquid crystal (LC) molecules on photosensitive alignment layers has been investigated. The layers, polyimides with photoisomerizable groups in their main chains, were irradiated with unpolarized near-UV (UPUV) light at oblique incidence. The irradiated film was found to align LC molecules homogene…
Polymer films are serving as passive regions in fast logic circuits and as active regions in organic optoelectronic devices, such as light-emitting diodes. Recent data illustrated the strong anisotropy in the thermal conductivity of polyimide films of thickness near 1 μm, with the in-plane value larger by a factor of…
The phase behavior of intermediately segregated (χN = 45) poly(ethylene)-poly(ethylethylene) (PE–PEE) diblock copolymers and PE–PEE binary blends are characterized using transmission electron microscopy and small-angle X-ray scattering. Surprisingly, the preparation-dependent, nonequilibrium phase behavior can be over…