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。
We report simultaneous amplified spontaneous emission from two different multiexcitonic transitions −1Se–1S3∕2 and 1Pe–1P3∕2− of colloidal CdSe nanocrystals (NCs) stabilized in high volume fraction in titania matrices. Two-state lasing from both multiexcitonic transitions is achieved in a surface-emitting distributed…
Abstract Summary: An advanced isoconversional method has been applied to determine the effective activation energies ( E ) for the glass transition in polystyrene (PS), poly(ethylene terephthalate) (PET), and boron oxide (B 2 O 3 ). The values of E decrease from 280 to 120 kJ · mol −1 in PS, from 1 270 to 550 kJ mol −…
The relationship of the microstructure of supercooled, highly viscous glycerol to the temperature dependence of its density, thermal expansion coefficient, and shear viscosity are discussed. The character of this temperature dependence at the transition from low viscosity state to the solid amorphous state (solidified…
The synthesis by hot pressing and wide-band (10Hz–1MHz) magnetoelectric (ME) characterization of bulk composites of nickel zinc ferrite Ni1−xZnxFe2O4 (NZFO) (x=0–0.5) and lead zirconate titanate (PZT) are reported. Hot-pressed samples show an order of magnitude improvement in ME voltage coefficient compared to sintere…
The basic concepts and characteristics of Raman spectra from single-wall carbon nanotubes (SWNTs, both isolated and bundled) are presented. The physical properties of the SWNTs are introduced, followed by the conceptual framework and characteristics of their Raman spectra. Each Raman feature, namely the radial breathi…
A systematic approach to study the phase stability of ${\mathrm{L}\mathrm{i}\mathrm{B}\mathrm{H}}_{4}$ based on ab initio calculations is presented. Three thermodynamically stable phases are identified and a new phase of $Cc$ symmetry is proposed for the first time for a complex hydride. The x-ray diffraction pattern…
The defect structure of bulk and nano-indium-tin oxide was investigated by a combination of experimental techniques, including high-resolution synchrotron x-ray diffraction, extended x-ray absorption fine structure, and time-of-flight neutron diffraction on powder specimens. The structural results include atomic posit…
Ab initio electronic structure calculations based on gradient corrected density-functional theory were performed on a class of novel quaternary compounds AgPb(m)SbTe(2+m), which were found to be excellent high temperature thermoelctrics with a large figure of merit ZT approximately 2.2 at 800 K. We find that resonant…
We experimentally and theoretically studied a new left-handed (LH) structure based on a photonic crystal (PC) with a negative refractive index. The structure consists of triangular array of rectangular dielectric bars with dielectric constant 9.61. Experimental and theoretical results demonstrate the negative refracti…
We review basic computational techniques for simulations of various magnetic properties of solids. Several applications to compute magnetic anisotropy energy, spin wave spectra, magnetic susceptibilities and temperature dependent magnetisations for a number of real systems are presented for illustrative purposes.
A computer program LMTART for electronic structure calculations using full potential linear muffin-tin orbital method is described
We present optical measurements of random arrays of aligned carbon nanotubes, and show that the response is consistent with conventional radio antenna theory. We first demonstrate the polarization effect, the suppression of the reflected signal when the electric field of the incoming radiation is polarized perpendicul…
BiFeO 3 was studied as an alternative environmentally clean ferro/piezoelectric material. 200-nm-thick BiFeO3 films were grown on Si substrates with SrTiO3 as a template layer and SrRuO3 as bottom electrode. X-ray and transmission electron microscopy studies confirmed the epitaxial growth of the films. The spontaneous…
Abstract Failures, due to stress corrosion cracking (SCC), of corrosion resistant alloy (CRA) production tubing or sand control screens have been reported in recent years. Increased use of CRA materials for downhole applications is the result of stringent requirements for high-temperature high-pressure and sweet/sour…
Single crystals of K 2 Mg 2 (SCN) 6 ·3H 2 O were obtained by the reaction of the binary compounds MgCl 2 · x H 2 O and KSCN at 220° using the Bridgman technique. The compound crystallizes hexagonally with the noncentrosymmetric space group P 6 3 cm ( Z = 2, a = 885.2(1) pm, c = 1732.7(3) pm, R1 all = 0.1035). In the c…
Abstract Ordered three-dimensional (3-D) cage-like mesoporous mixed tungsten–titanium oxides (WO3–TiO2) with relatively high surface area (152 m2g−1) have been synthesized by employing Pluronic F108 triblock copolymer as a structure-directing agent via “acid-base pairs” strategy. Such materials exhibit enhanced electr…
Muons as a probe of magnetism in molecule-based low dimensional magnets, Tom Lancaster, Stephen J Blundell, Francis L Pratt, Michael L Brooks, Jamie L Manson, Euan K Brechin, Cyril Cadiou, David Low, Eric J L McInnes, Richard E P Winpenny
Previously it was shown by experiments that nanophase separation of incompatible main- and side-chain parts occurs in higher poly( n -alkyl acrylates) (P n AA) and poly( n -alkyl methacrylates) (P n AMA). Alkyl groups of different monomeric units of the polymer aggregate in the melt and form self-assembled alkyl nanod…
The syntheses and metal-responsive properties of poly(p-phenyleenethynylene)s with grafted new pseudo-crown-ether groups are reported. These polymers exhibit high sensitivities to alkali ions because of their collective optical properties, which are very sensitive to ion-induced conformational changes. The quenching o…
A molecular dyad has been synthesized in which free-base porphyrin and ruthenium(II) bis(2,2‘:6‘,2‘ ‘-terpyridine) subunits are linked via a meso -phenylene group. The distal terpyridine ligand bears a single phenylethynylene group. Selective illumination into the metal complex is followed by rapid intramolecular trip…