Materials Literature
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We report on transparent Ni 2+ -doped MgO–Al 2 O 3 –SiO 2 glass ceramics with broadband infrared luminescence. Ni 2+ -doped MgO–Al 2 O 3 –SiO 2 glass is prepared by using the conventional method. After heat treatment at high temperature, MgAl 2 O 4 crystallites are precipitated, and their average size is about 4.3 nm.…
Abstract Two new phenyl‐ and naphthyl‐substituted rigid‐rod aromatic dicarboxylic acid monomers, 2,2′‐diphenylbiphenyl‐4,4′‐dicarboxylic acid ( 4 ) and 2,2′‐di(1‐naphthyl)biphenyl‐4,4′‐dicarboxylic acid ( 5 ), were synthesized by the Suzuki coupling reaction of 2,2′‐diiodobiphenyl‐4,4′‐dicarboxylic acid dimethyl ester…
Aromatic polyimides having phenyl groups at the 2- and 2′-positions of the diphenyl ether moiety were synthesized from bis(4-amino-2-biphenyl) ether and various tetracarboxylic dianhydrides by the conventional two-step procedure using N-methyl-2-pyrrolidone (NMP) as a solvent [Morikawa et al., Polymer Journal37, 759,…
Abstract The polyaniline/iron nanocomposites with both conducting and magnetic properties have been prepared by cryomilling (high‐energy ball milling under cryogenic temperature), in which the average size of iron grains attains 20 nm. Enhanced coercivity of 206 Oe and decreased conductivity of 0.1 S cm −1 at room tem…
A cellular automaton (CA)-based model for the precise two-dimensional simulation of the dendritic morphology of cast aluminum alloys was developed. Compared with previous CA models, the new model considers the solidification process in more detail, solving the solute and heat conservation equations in the modeling dom…
Acid-catalyzed condensation of a pyrrole bisacrylaldehyde with a tripyrrane, followed by oxidation with ferric chloride, gave a [22]porphyrin-(3.1.1.3). This stretched macrocycle shows a strong diamagnetic ring current by (1)H NMR spectroscopy and gives red-shifted porphyrin-like UV-vis spectra; coordination with pall…
The self-assembly of four symmetrically substituted tri-aryl-benzene derivatives of formula C 24 H 15 X 3, where X = H ( 1 ), Cl ( 2 ), COOMe ( 3 ), and COOH ( 4 ), was studied as a function of the substituent X. Crystal packing analysis of compounds 1 − 3 showed that in 1, there are no strong face-to-face stacking in…
Stable organosols of silver nanoparticles (AgNPs) without any capping agents have been synthesized by an electrochemical dissolution of a sacrificing silver electrode in dimethyl sulfoxide (DMSO). The peak at 425 +/- 5 nm observed in the UV-vis spectra was attributed to the surface plasmon resonance for silver. The fo…
Abstract A novel approach to fabricate polymer brushes on the surface of carbon nanotubes (CNTs) is proposed. Carboxyl groups on the surface of chemically oxidized CNTs were reacted with hexamethylene diisocyanate, followed by a reaction with methacrylamide to give terminal vinyl groups‐functionalized CNTs, so called…
Measurements of polarization and temperature dependent soft x-ray absorption have been performed on ${\mathrm{Na}}_{x}\mathrm{Co}{\mathrm{O}}_{2}$ single crystals with $x=0.4$ and $x=0.6$. They show a deviation of the local trigonal symmetry of the $\mathrm{Co}{\mathrm{O}}_{6}$ octahedra, which is temperature independ…
Transport through zinc blende magnetic semiconductors with magnetic domain walls is studied theoretically. We show that these magnetic domain walls have an intrinsic resistance due to the effective hole spin-orbit interaction. The intrinsic resistance is independent of the domain-wall shape and width and survives the…
Abstract Light illumination of single-wall carbon nanotubes (SWCNTs) dispersed with anthracene (An) dendrons afforded the accumulation of the reduced form of methyl viologen in the presence of a hole shifter. With the helps of the fluorescence lifetime and transient absorption measurements, the charge-separation proce…
Continuum theory of moving dislocations is used to set up a non-local constitutive law for crystal plasticity in the form of partial differential equations for evolving dislocation fields. The concept of single-valued dislocation fields that enables us to keep track of the curvature of the continuously distributed gli…
We observed the lowest optical transitions $({E}_{11}^{S})$ in separated carbon nanotubes by resonant Raman spectroscopy. Radial breathing mode spectra were collected varying the excitation energy in the near-infrared from $1.15\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}1.48\phantom{\rule{0.3em}{0e…
We present a method for performing multiexciton spectroscopy in colloidal semiconductor nanocrystals. In this regime multiexcitonic states are generated sequentially via a ``ladder-climbing'' mechanism. The distribution of multiexcitonic states, determined by a steady-state rate equation, adiabatically follows the ill…
A series of alternating copolyimides (altPIs) having highly blue fluorescing 9,10-diphenyl-anthracene units were synthesized and the photoluminescence of the altPIs were investigated. The alt-PIs were prepared by sequential addition of two diamines to a solution of spiroalicyclic tetracarboxylic dianhydride, rel[1R,5S…
A series of well-defined brush polyimide (PI) composed of two 4- n-alkyloxyphenyloxy bristles per repeat unit on a semi-rigid poly(4,4′-methylenyldiphenylene pyromellitimide), Cm-PMDA-MDA PIs, were synthesized and their nanoscale thin films prepared by conventional spin-coating of their soluble poly(amic acid) precurs…
Fluorescence modulation by a class of photochromic perimidine spirodimers, which exhibit a characteristic fluorescence associated with their photochromic reactions, has been described. Upon irradiation using 365 nm light, these non-fluorescent spiro molecules undergo a thermally-reversible ring opening at their spiro…
Four novel sulfonated diamine monomers which are isomers to each other, 4,4′-bis(4-aminophenoxy)biphenyl-3,3′-disulfonic acid ( pBAPBDS), 4,4′-bis(3-aminophenoxy)biphenyl-3,3′-disulfonic acid ( mBAPBDS), 2,2′-bis(4-aminophenoxy)biphenyl-5,5″-disulfonic acid ( oBAPBDS), and 4,4--bis(4-amino-2-sulfophenoxy)biphenyl ( iB…
Abstract Electrical relaxation and conductivity processes in amorphous and semicrystalline poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN) homopolymers and certain PET/PEN copolymers have been studied by means of dielectric spectroscopy. Homopolymers and copolymers able to crystallize were subj…