Materials Literature
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We investigate the cohesive energy, heat of formation, elastic constant and electronic band structure of transition metal diborides TMB 2 (TM = Hf, Ta, W, Re, Os and Ir, Pt) in the Pmmn space group using the ab initio pseudopotential total energy method. Our calculations indicate that there is a relationship between e…
Don't forget your coat! Monodispersed Mn3O4 nanoparticles, each encased in a thin shell of MnO2, have been prepared for the first time. Ordered three-dimensional arrays of cubic symmetry were formed by self-assembly (see transmission electron microscope image). The nanoparticles exhibit strong interactions between the…
"Bottom-up" methods to obtain nanocrystals usually result in metastable phases, even in processes carried out at room temperature or under soft annealing conditions. However, stable phases, often associated with anisotropic shapes, are obtained in only a few special cases. In this paper we report on the synthesis of t…
Contrary to conventional wisdom, our purified La 2-2x Sr 1+2x Mn2O7 crystals exhibit CE-type orbital and charge order as the low-temperature ground state for a hole doping level h=0.5. For small deviations from h=0.5, the high-temperature CE phase is replaced at low temperatures by an A-type antiferromagnet without co…
Abstract The effects of tungsten doping in La 2 Mo 2– x W x O 9 samples ( x = 0, 0.1, 0.25, 0.5, 0.75, 1.0, 1.2, 1.4) were studied using dielectric relaxation measurements. Additional to the low‐temperature relaxation peak P d associated with oxygen ion diffusion, a new dielectric loss peak P h was observed around 740…
Abstract Model poly[ethylene‐ block ‐( L , L ‐lactide)] (PE‐ block ‐PLA) block copolymers were successfully synthesized by combining metallocene catalyzed ethylene oligomerization with ring‐opening polymerization (ROP) of L , L ‐lactide (LA). Hydroxy‐terminated polyethylene (PE‐OH) macroinitiator was prepared by means…
The crystal structures, including two new polymorphs, of three diastereomerically related salt pairs formed by (R)-1-phenylethylammonium (1) with (S&R)-2-phenylpropanoate (2), (S&R)-2-phenylbutyrate (3), and (S&R)-mandelate (4) ions were characterized by low-temperature single crystal or powder X-ray diffraction. Ther…
3D nanostructured quasicrystalline materials significantly larger than feasible with previously reported techniques are produced. 2D quasiperiodic surface relief templates with 8mm point group symmetry are made by multiple-exposure interference lithography. Phase-mask lithography with corresponding PDMS masks produce…
Back and forth: The two complexes [{P2W15O54(H2O)2}2Zr]12− and [{P2W15O54(H2O)2}Zr{P2W17O61}]14− exhibit extensive dynamic structural changes induced by completely reversible multiple protonation behavior, comparable to the flexing of a muscle (see picture). The pH titration of the former complex indicates a two-step…
A dithienylethene derivative containing a cyclobutene-1,2-dione skeleton does not exhibit photochromic properties. However, when both ketone functions are protected with cyclic acetal groups, photochromic behavior is observed.
Ab initio quantum mechanical calculations have been performed to establish the potentials for alkyl-substituted polyhedral oligomeric silsesquioxane (POSS) monomers RxH8-x(SiO1.5)8. More specifically, we have examined the unsubstituted POSS (SiO1.5H)8 cage as well as linear and cyclic alkyl-substituted cages where one…
(Bi 1.5 Zn 0.5 )(Zn 0.5 Nb 1.5 )O 7 (BZN) films with different thicknesses and preferred orientations have been fabricated on Nb doped SrTiO 3 substrates by pulsed laser deposition. As the thickness increases, the permittivity increases, and the dielectric loss decreases, while the tunability only has a little variati…
BphD of Burkholderia xenovorans LB400 catalyzes an unusual C-C bond hydrolysis of 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid (HOPDA) to afford benzoic acid and 2-hydroxy-2,4-pentadienoic acid (HPD). An enol-keto tautomerization has been proposed to precede hydrolysis via a gem-diol intermediate. The role of the can…
Zn 0.8 Mg 0.2 O metal–semiconductor–metal ultraviolet photodiodes were fabricated on quartz by radio frequency magnetron sputtering. Dark current, spectral responsivity and pulse response experiments were carried out for the device. The photodetectors showed a peak responsivity at 330 nm. The ultraviolet-visible rejec…
The 3D coordination polymer [Fe(4ditz)3](PF6)2.solv consists of three interpenetrating infinite networks. There are cavities between iron atoms of different networks, which are partly filled with solvent molecules. With a change of the solvent used during synthesis from methanol to ethanol, the magnetic behavior of th…
Circular differential transmission in thick films (1.1 mum) of poly{9,9-bis[(3S)-3,7-dimethyloctyl]-2,7-fluorene} is investigated. The vitrified liquid crystalline film obtained after annealing shows high circular differential transmission of light in the wavelength range where the polyfluorene does not absorb (lambda…
The Brownian fluctuations of the colloidal tracers often used in microscale velocimetry are typically isotropic in the bulk. In the near-wall region, however, these fluctuations are strongly affected by the hydrodynamic interaction with the wall and by the no-flux condition imposed by the wall. These wall effects can,…
This paper describes the fabrication of polyelectrolyte multilayer film which combines preassembly of poly(allylamine hydrochloride) (PAH) and 5,10,15,20-tetraphenyl-21H,23H-porphine-p,p',p' ',p' ''-tetrasulfonic acid tetrasodium hydrate (TPPS) in aqueous solution with the layer-by-layer (LbL) assembly of the PAH-TPPS…
The electrochemical behavior of the ball-shaped heteropolytungstates [[Sn(CH(3))(2)(H(2)O)](24)[Sn(CH(3))(2)](12)(A-XW(9)O(34))(12)](36-) (X=P, 1; As, 2) was examined in aqueous electrolytes by redissolution of their respective mixed cesium-sodium salts Cs(14)Na(22)[[Sn(CH(3))(2)(H(2)O)](24)[Sn(CH(3))(2)](12) (A-PW(9)…
The effect of Cr substitution into nanocrystalline Co-Zn ferrite prepared by the chemical coprecipitation method has been studied. M\"ossbauer studies at a temperature $(20\phantom{\rule{0.3em}{0ex}}\mathrm{K})$ well below the blocking temperatures of the samples show that Cr goes preferentially into the octahedral $B…