Materials Literature
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The key to rapid temperature programmed separations with gas chromatography are a fast, low-volume injection and a short microbore separation column with fast resistive heating. One of the major problems with the reduction of column dimensions for micro gas chromatography is the availability of a stationary phase that…
We report the effect of nonmagnetic Ti4+ impurities on the electronic and magnetic properties of Sr3Ru2O7. Small amounts of Ti suppress the characteristic peak in magnetic susceptibility near 16 K and result in a sharp upturn in specific heat. The metamagnetic quantum phase transition and related anomalous features ar…
Under a certain scaling, the electron densities of finite systems become both large and slowly-varying, so that the gradient expansions of the density functionals for the Kohn-Sham kinetic and exchange energies become asymptotically exact to order $\nabla^2$. Neutral atoms of large $Z$ scale similarly, but a cusp corr…
A mechanism is proposed for manipulating the magnetic state of a helical spin density wave using a current. In this paper, we show that a current through a bulk system with a helical spin density wave induces a spin transfer torque, giving rise to a rotation of the order parameter.The use of spin transfer torque to ma…
Single-particle tracking experiments have been used widely to study the heterogeneity of a sample. Segments with dissimilar diffusive behaviors are associated with different intermediate states, usually by visual inspection of the tracking trace. A likelihood-based, systematic approach is presented to remove this ince…
Amphiphilic phospholipids were used to direct the formation of biocompatible, uniform silica nanostructures in the presence of Saccharomyces cerevisiae and bacterial cell lines. The cell surfaces organize multilayered phospholipid vesicles that interface coherently with the silica host and help relieve drying stresses…
We report the results of molecular dynamics simulations of the release of five species of noble gas atoms trapped inside a small cluster of fullerenes in the temperature range 4000K < T < 5000K. We find that larger noble gas atoms are generally released at a slower rate and that helium is released considerably more ra…
Using the recently developed $N\text{th}$-order muffin-tin-orbital (NMTO) based downfolding technique we revisit the electronic properties of half-metallic ferromagnets, the semi-Heusler NiMnSb and rutile $\mathrm{Cr}{\mathrm{O}}_{2}$. The NMTO Wannier orbitals for the $\mathrm{Mn}\text{\ensuremath{-}}d$ and $\mathrm{…
Abstract The high‐yield fabrication of tetrapodal CdSe, CdTe, and CdSe x Te 1– x nanocrystals is systematically studied. CdSe nanocrystals are prepared by first controlling the synthesis of high‐quality wurtzite CdSe and zinc blende CdSe nanocrystals at a relatively high temperature (260 °C) by selecting different lig…
Stable dispersions of molecularlike aggregates of CdTe quantum dots are prepared by chemical cross-linking. Cryo-TEM images confirm the presence of cross-linked quantum dots and show that the size of the small aggregates can be controlled by the amount of cross-linker added. Optical measurements reveal two types of in…
In this paper, we prepared composite fibers via electrospinning from either W/O or O/W emulsion. SEM images demonstrate the beads-in-string structures in these fibers and proved this technique to be an effective method for microencapsulation. As a practical application, Ca-alginate microspheres, which serve as reservo…
Mesoporous beads are promising materials for embedding functional nanoparticles because of their nanometer-sized pores and large surface areas. Here we report the development of silica microbeads embedded with both semiconductor quantum dots (QD) and iron oxide (Fe3O4) nanocrystals as a new class of dual-function carr…
A multiscale theoretical approach is used for the investigation of hydrogen storage in silicon-carbon nanotubes (SiCNTs). First, ab initio calculations at the density functional level of theory (DFT) showed an increase of 20% in the binding energy of H2 in SiCNTs compared with pure carbon nanotubes (CNTs). This is exp…
In a piezoelectric material, an applied uniform strain can induce an electric polarization (or vice versa). Crystallographic considerations restrict this technologically important property to noncentrosymmetric systems. It has been shown both mathematically and physically that a nonuniform strain can potentially break…
We report a macroscopic shrinkage by up to 30 vol % during electrochemical dealloying of Ag-Au. Since the original crystal lattice is maintained during the process, we suggest that the formation of nanoporous gold in our experiments is accompanied by the creation of a large number of lattice defects and by local plast…
Abstract Summary: By incorporation of surface‐modified superparamagnetic nanoparticles into shape memory polymer matrices, remote actuation of complex shape transitions by electromagnetic fields is possible. The composite thermosets of oligo( ε ‐caprolactone)dimethacrylate/butyl acrylate contain between 2 and 12 wt.‐%…
The first rigid-rod cluster-containing σ-alkynyl polymers E−[({Pt 6 }−CC−Ar−CC)] x - {Pt6 }−E [( 3 ), {Pt 6 } = Pt 6 (μ-PBu t 2 ) 4 (CO) 4, E = end group; M n = 22 000−38 000] have been prepared by step-growth polycondensation of {Pt 6 }Cl 2 and 1,4-didodecyl-2,5-diethynylbenzene (HCC−Ar−CCH) under Sonogashira-type co…
It is shown that nanowires and quantum dots of cubic material have a dielectric function that obeys the Clausius-Mossotti relation. We discuss the relationship between dipole summations in these materials and the dielectric function.
A pyroelectric crystal [Cu(NH 3 ) 2 ] 2 [Mo(CN) 8 ] ( Fdd 2), which is thermally stable up to 150 °C, is synthesized, and this compound displays a strong second harmonic generation of 1.8 × 10 -10 esu.
A systematic experimental study has been carried out on the efficiency of bimetallic catalysts based on Ni and the rare-earth elements Y, La, Ce, Nd, Gd, Tb, Dy, Ho, Er, and Lu (group A) and Eu, Sm, Yb, and Tm (group B) in the synthesis of single-walled carbon nanotubes (SWNTs). The two groups give quite different res…