Materials Literature
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A novel oxygen storage material consisting of Ce-substituted La-oxysulfate, (La 1− x Ce x ) 2 O 2 SO 4 (0 ≤ x ≤ 0.2), was synthesized via a surfactant-assisted route. The layered mesophase templated by dodecyl sulfate anion (DS = C 12 H 25 OSO 3 − ) was precipitated from aqueous solutions of nitrates using ammonia as…
A stochastic cellular automata simulator capable of spatiotemporal modeling of the crystallization and amorphization behavior of phase-change materials during the complex annealing cycles used in optical and electrical memory applications is presented. This is based on consideration of bulk and surface energies to gen…
ZnO(0001) substrates were ion implanted with 100 keV of Co and 300 keV of Gd at different fluences ranging from 5×1013–1×1015/cm2. The resulting Co:ZnO and Gd:ZnO samples were analyzed with respect to their structural, magnetic, and optical properties. The effect of annealing at 350 °C on the structure and the resulti…
Multiferroics, which exhibit both ferroelectricity and ferromagnetism, are currently under intensive investigation. Their spontaneous polarization and saturation magnetization are very low in comparison to many standard ferroelectrics and ferromagnets. In order to explain the experimentally observed enhanced polarizat…
Synergistic dipole-dipole and hydrogen-bonding interactions are used to assemble nanostructured materials. Precipitation of a hydrogen-bonding donor-acceptor molecule 8-[[p-[bis(ethyl)amino]phenyl]azo]-isobutylflavin (ABFL) yields nanowires approximately 50-150 nm in diameter and lengths of several millimeters. Precip…
Ab initio electronic-structure calculations were performed by using density functional theory with polarized basis set (LanL2DZ) within the spin polarized generalized gradient approximation for metal (M=Ti,Zr,Hf) doped Sin clusters where n varies from 9 to 20. In the first step of the calculation, geometrical optimiza…
The self-assembly of surfactant molecules on crossing carbon nanotubes has been investigated using a bead-spring model and implicit solvent dissipative particle dynamics simulations. Adsorption is directed to the nanotube crossing by its higher hydrophobic potential which is due to the presence of two surfaces. As a c…
Unlike ideal 180° ferroelectric walls that are a unit cell wide (∼0.5 nm), real walls in ferroelectrics have been reported to be many nanometers wide (1–10 nm). Using scanning nonlinear dielectric microscopy of lithium niobate (LiNbO3) and lithium tantalate (LiTaO3) ferroelectrics, we show that the wall width at surfa…
The fundamental role of aryl diazonium salts for post-synthesis selectivity of carbon nanotubes is investigated using extensive electronic-structure calculations. The resulting understanding for diazonium-salt-based selective separation of conducting and semiconducting carbon nanotubes shows how the primary contributi…
Concerns are expressed regarding the interpretation of absorption spectra for colloidal quantum dots. Using the work presented in this journal by R. Koole et al. ( Small , 2008 , 4 , 127) as an example, the correspondents cast doubt on the role of Raleigh scattering as a background source in these spectra, and the use…
Nano-structure, magnetic and optical properties of Co-doped ZnO films prepared by a wet chemical method, Wang, Aihua, Zhang, Binglin, Wang, Xinchang, Yao, Ning, Gao, Zhifeng, Ma, Yukun, Zhang, Lan, Ma, Huizhong
The enzyme threonine deaminase (TD) is a key regulatory enzyme in the pathway for the biosynthesis of isoleucine. TD is inhibited by its end product, isoleucine, and this effect is countered by valine, the product of a competing biosynthetic pathway. Sequence and structure analyses have revealed that the protomers of…
Electric field induced second harmonic measurements applying femtosecond laser pulses (1.59 eV, 80±5 fs, 80 MHz) to substantially boron doped p+-Si/SiO2 interfaces reveal a temporal evolution of the second harmonic (SH) signal, which differs drastically from that of weakly doped samples. A significant initial SH signa…
Effects of coagulation temperature, coagulants, and wet-spinning methods on structure and properties of novel regenerated cellulose (RC) fibers prepared from cellulose in 7.5 wt % NaOH/11 wt % urea aqueous solution on pilot scale spinning machine by one- and two-stage coagulation were investigated by tensile testing,…
Diameter controlled vertically aligned single walled carbon nanotubes (VA-SWNTs) were synthesized by controlling flow rate of carbon source and dimension of catalyst nanoparticles. The large scale structural analysis demonstrating spatial distribution of SWNT diameters was conducted by a newly developed Raman Radial B…
ZnO nanostructures were grown on Au-catalyzed Si silicon substrates using vapor phase transport at growth temperatures from 800 to 1150 °C. The sample location ensured a low Zn vapor supersaturation during growth. Nanostructures grown at 800 and 850 °C showed a faceted rodlike morphology with mainly one-dimensional (1…
In this paper, we present a room-temperature electroluminescence (EL) study of amorphous nonstoichiometric silicon nitride (SiNX) films. The light-emitting device is formed by an ITO/SiNX/p-type silicon structure. EL shows a yellowish broad emission spectrum with a power efficiency of 10−6. The EL peak energy depends…
Using conducting-tip atomic force microscopy (C-AFM), we study the spatial distribution of current paths and local electrical properties in carbon nanofiber/polymer nanocomposites. Previous studies of similar systems were hindered by a polymer-rich skin layer that exists at the nanocomposite surfaces. We present an ex…
The synthesis and structures of the perovskites Ln 1/3 TaO 3 are described. As the size of the Ln cation is reduced, the compounds display a sequence of structure: P 4/ m m m /La → C m m m /Ce−Gd → P m m a /Tb, Dy → P m c 2 1 /Ho, Er. Although apparently tetragonal in P 4/ mmm, electron diffraction patterns of Tm 1/3…
The self-assembly of hybrid diblock copolymers composed of poly(HPMA) and beta-sheet peptide P11 (CH(3)CO-QQRFQWQFEQQ-NH(2)) blocks was investigated. Copolymers were synthesized via thiol-maleimide coupling reaction, by conjugation of semitelechelic poly(HPMA)-SH with maleimide-modified beta-sheet peptide. As expected…